Source http://www.jammu-kashmir.com/documents/jkindiancomplaintun.html

Letter Dated 1 January, 1948, from the Representative of India to the President of the Security Council (S/628). 
The Government of India have instructed me to transmit to you the following telegraphic communication : 
"1. Under Article 35 of the Charter of the United Nations, any Member may bring any situation whose continuance is likely to endanger the maintenance of international peace and security to the attention of the Security Council. Such a situation now exists between India and Pakistan owing to the aid which invaders, consisting of nationals of Pakistan and of tribesmen from the territory immediately adjoining Pakistan on the north-west, are drawing from Pakistan for operations against Jammu and Kashmir, a State which has acceded to the Dominion of India and is part of India. The circumstances of accession, the activities of the invaders which led the Government of India to take military action against them, and the assistance which the attackers have received and are still receiving from Pakistan are explained later in this memorandum. The Government of India request the Security Council to call upon Pakistan to put an end immediately to the giving of such assistance, which is an act of aggression against India. If Pakistan does not do so, the Government of India may be compelled, in self-defence, to enter Pakistan territory, in order to take military action against the invaders. The matter is, therefore, one of extreme urgency and calls for immediate action by the Security Council for avoiding a breach of international peace. 
"2. From the middle of September 1947, the Government of India had received reports of the infiltration of armed raiders into the western parts of Jammu Province of the Jammu and Kashmir State; Jammu adjoins West Punjab which is a part of the Dominion of Pakistan. These raiders had done a great deal of damage in that area and taken possession of part of the territory of the State. On 24 October, the Government of India heard of a major raid from the Frontier Province of the Dominion of Pakistan into the Valley of Kashmir. Some two thousand or more fully armed and equipped men came in motor transport, crossed over to the territory of the State of Jammu and Kashmir, sacked the town of Muzaffarabad, killing many people, and proceeded along the Jhelum Valley road towards Srinagar, the summer capital of the Jammu and Kashmir State. Intermediate towns and villages were sacked and burnt, and many people killed. These raiders were stopped by Kashmir State troops near Uri, a town some fifty miles from Srinagar, for some time, but the invaders got around them and burnt the power house at Mahora, which supplied electricity to the whole of Kashmir. 
"3. The position, on the morning of 26 October, was that these raiders had been held by Kashmir State troops and part of the civil population, who had been armed, at a town called Baramulla. Beyond Baramulla there was no major obstruction up to Srinagar. There was immediate danger of these raiders reaching Srinagar, destroying and massacring large numbers of people, both Hindu and Muslims. The State troops were spread out all over the State and most of them were deployed along the western border of Jammu Province. They had been split up into small isolated groups and were incapable of offering effective resistance to the raiders. Most of the State officials had left the threatened area and the civil administration had ceased to function. All that stood between Srinagar and the fate which had overtaken the places en route followed by the raiders was the determination of the inhabitants of Srinagar, of all communities, and practically without arms, to defend themselves. At this time Srinagar had also a large population of Hindu and Sikh refugees who had fled there from West Punjab owing to communal disturbances in that area. There was little doubt that these refugees would be massacred if the raiders reached Srinagar. 
"4. Immediately after the raids into the Jammu and Kashmir State commenced, approaches were informally made to the Government of India for the acceptance of the accession of the State to the Indian Dominion. (It might be explained in parenthesis that Jammu and Kashmir form a State whose ruler, prior to the transfer of power by the United Kingdom to the Dominions of India and Pakistan, had been in treaty relations with the British Crown, which controlled its foreign relations and was responsible for its defence. The treaty relations ceased with the transfer of power on 15 August last, and Jammu and Kashmir like other States acquired the right to accede to either Dominion.) 
"5. Events moved with great rapidity, and the threat to the Valley of Kashmir became grave. On 26 October, the ruler of the State, His Highness Maharaja Sir Hari Singh, appealed urgently to the Government of India for military help. He also requested that the Jammu and Kashmir State should be allowed to accede to the Indian Dominion. An appeal for help was also simultaneously received by the Government of India from the largest popular organisation in Kashmir, the National Conference, headed by Sheikh Mohammed Abdullah. The Conference further strongly supported the request for the State's accession to the Indian Dominion. The Government of India were thus approached not only officially by the State authorities, but also on behalf of the people of Kashmir, both for military aid and for the accession of the State to India. 
" 6. The grave threat to the life and property of innocent people in the Kashmir Valley and to the security of the State of Jammu and Kashmir that had developed as a result of the invasion of the Valley demanded immediate decision by the Government of India on both the requests. It was imperative on account of the emergency that the responsibility for the defence of the Jammu and Kashmir State should be taken over by a government capable of discharging it. But, in order to avoid any possible suggestion that India had utilised the State's immediate peril for her own political advantage, the Government of India made it clear that once the soil of the State had been cleared of the invader and normal conditions restored, its people would be free to decide their future by the recognised democratic method of a plebiscite or referendum which, in order to ensure complete impartiality, might be held under international auspices. 
"7. The Government of India felt it their duty to respond to the appeal for armed assistance because : 
(1) They could not allow a neighbouring and friendly State to be compelled by force to determine either its internal affairs or its external relations; 
(2) The accession of the Jammu and Kashmir State to the Dominion of India made India really responsible for the defence of the State. 
"8. The intervention of the Government of India resulted in saving Srinagar. The raiders were driven back from Baramulla to Uri and are held there by Indian troops. Nearly 19,000 raiders face the Dominion forces in this area. Since operation in the Valley of Kashmir started, pressure by the raiders against the western and south-western border of the Jammu and Kashmir State has been intensified. Exact figures are not available. It is understood, however, that nearly 15,000 raiders are operating against this part of the State. State troops are besieged in certain areas. Incursions by the raiders into the State territory, involving murder, arson, loot, and the abduction of women, continue. The booty is collected and carried over to the tribal areas to serve as an inducement to the further recruitment of tribesmen to the ranks of the raiders. In addition to those actively participating in the raid, tribesmen and others, estimated at 100,000, have been collected in different places in the districts of West Punjab bordering the Jammu and Kashmir State, and many of them are receiving military training under Pakistani nationals, including officers of the Pakistan Army. They are looked after in Pakistan territory, fed, clothed, armed and otherwise equipped, and transported to the territory of the Jammu and Kashmir State with the help, direct and indirect, of Pakistani officials, both military and civil. 
"9. As already stated, the raiders who entered the Kashmir Valley in October came mainly from the tribal areas to the north-west of Pakistan and, in order to reach Kashmir, passed through Pakistan territory. The raids along the south-west border of the State, which had preceded the invasion of the valley proper, had actually been conducted from Pakistan territory, and Pakistan nationals had taken part in them. This process of transmission across Pakistan territory and utilisation of that territory as a base of operations against the Jammu and Kashmir State continues. Recently, military operations against the western and south-western borders of the State have been intensified, and the attackers consist of nationals of Pakistan as well as tribesmen. These invaders are armed with modern weapons, including mortars and medium machine-guns, wear the battle dress of regular soldiers and, in recent engagements, have fought in regular battle formation and are using the tactics of modern warfare. Man-pack wireless sets are in regular use and even mark V mines have been employed. For their transport the invaders have all along used motor vehicles. They are undoubtedly being trained and to some extent led by regular officers of the Pakistan Army. Their rations and other supplies are obtained from Pakistan territory. 
"10. These facts point indisputably to the conclusion 
"(a) That the invaders are allowed transit across Pakistan territory; 
"(b) That they are allowed to use Pakistan territory as a base of operations; 
"(c) That they include Pakistan nationals; 
"(d) That they draw much of their military equipment, transportation, and supplies (including petrol) from Pakistan; and 
"(e) That Pakistan officers are training, guiding, and otherwise actively helping them. 
"There is no source other than Pakistan from which they could obtain such quantities of modern military equipment, training or guidance. More than once, the Government of India had asked the Pakistan Government to deny to the invaders facilities which constitute an act of aggression and hostility against India, but without any response. The last occasion on which this request was made was on 22 December, when the Prime Minister of India handed over personally to the Prime Minister of Pakistan a letter in which the various forms of aid given by Pakistan to the invaders were briefly recounted and the Government of Pakistan were asked to put an end to such aid promptly; no reply to this letter has yet been received in spite of a telegraphic reminder sent on 26 December. 
"11. It should be clear from the foregoing recital that the Government of Pakistan are unwilling to stop the assistance in material and men which the invaders are receiving from Pakistan territory and from Pakistan nationals, including Pakistan Government personnel, both military and civil. This attitude is not only un-neutral, but constitutes active aggression against India, of which the State of Jammu and Kashmir forms a part. 
"12. The Government of India have exerted persuasion and exercised patience to bring about a change in the attitude of Pakistan. But they have failed, and are in consequence confronted with a situation in which their defence of the Jammu and Kashmir State is hampered and their measures to drive the invaders from the territory of the State are greatly impeded by the support which the raiders derive from Pakistan. The invaders are still on the soil of Jammu and Kashmir and the inhabitants of the State are exposed to all the atrocities of which a barbarous foe is capable. The presence, in large number of invaders in those portions of Pakistan territory which adjoin parts of Indian territory other than the Jammu and Kashmir State is a menace to the rest of India. Indefinite continuance of the present operations prolongs the agony of the people of Jammu and Kashmir, is a drain on India's resources and a constant threat to the maintenance of peace between India and Pakistan The Government of India have no option, therefore, but to take more effective military action in order to rid the Jammu and Kashmir State of the invader. 
"13. In order that the objective of expelling the invader from Indian territory and preventing him from launching fresh attacks should be quickly achieved, Indian troops would have to enter Pakistan territory; only thus could the invader be denied the use of bases and cut off from his sources of supplies and reinforcements in Pakistan. Since the aid which the invaders are receiving from Pakistan is an act of aggression against India, the Government of India are entitled, under international law, to send their armed forces across Pakistan territory for dealing effectively with the invaders. However, as such action might involve armed conflict with Pakistan, the Government of India, ever anxious to proceed according to the principles and aims of the Charter of the United Nations, desire to report the situation to the Security Council under Article-35 of the Charter. They feel justified in requesting the Security Council to ask the Government of Pakistan : 
(1) To prevent Pakistan Government personnel, military and civil, 
from participating or assisting in the invasion of the Jammu and Kashmir State; 
(2) To call upon other Pakistani nationals to desist from taking any part in the fighting 
in the Jammu and Kashmir State; 
(3) To deny to the invaders : (a) access to any use of its territory for operations against Kashmir, (b) military and other supplies, (c) all other kinds of aid that might tend to prolong the present struggle. 
"14. The Government of India would stress the special urgency of the Security Council taking immediate action on their request. They desire to add that military operations in the invaded areas have, in the past few days, been developing so rapidly that they must, in self-defence, reserve to themselves the freedom to take, at any time when it may become necessary, such military action as they may consider the situation requires. 
"15. The Government of India deeply regret that a serious crisis should have been reached in their relations with Pakistan. Not only is Pakistan a neighbour but, in spite of the recent separation, India and Pakistan have many ties and many common interests. India desires nothing more earnestly than to live with her neighbour-State on terms of close and lasting friendship. Peace is to the interest of both States; indeed to the interests of the world. The Government of India's approach to the Security Council is inspired by the sincere hope that, through the prompt action of the Council, peace may be preserved. 
"16. The text of this reference to the Security Council is being telegraphed to the Government of Pakistan." 

Source: Government of India documents