Past midnight on 5/6 September, without a formal declaration of war, Indian Army crossed the international border and attacked Lahore and Kasur fronts.
Pakistan Army and Pakistan Air Force halted the attack in its tracks, inflicting heavy casualties on the aggressor. On 7 September a single Pakistan Air Force Pilot, Squadron Leader M.M. Alam, Sitara-i-Juraat, in his F-86 Sabre shot down five Indian Air Force attacking Hunter aircraft in a single sortie, an unbeaten world record “On night 6/7 September three teams of our Special Services Groups were para-dropped on Indian Air Force bases at Pathankot, Adampur and Halwara to neutralize them.
To relieve pressure on Lahore front, on night 7/8 September, after crossing two major water obstacles in a bold thrust, Pakistani armoured and mechanized formations supported by artillery and Pakistan Air Force overran area Khem Karn, 6 to 8 miles inside Indian territory. Vital Indian positions at Sulemanki and across Rajasthan and Sindh were also captured in bold, swift attacks.
On night 7/8 September, 1 Corps of Indian Army launched its main effort east of Sialkot with one armoured and three infantry divisions on our extended 15 Division front, screened only by gallant 3 Frontier Force and B Company 13 Frontier Force (Reconnaissance & Support). 24 Infantry Brigade (Brigadier A.A Malik, Hilal-i-Juraat) on the move in area Pasrur, rushed 25 Cavalry (Lieutenant Colonel Nisar Ahmad, Sitara-i-Juraat), on 8 September to delay and disrupt enemy thrusts. As soon as the presence of Indian 1 Armoured Division was confirmed, Pakistan Army rushed forward to stop the onslaught on a 30-mile front. The biggest tank battle since World War II was fought on the Chwinda front by 6 Armoured Division with under command 24 Infantry Brigade Groups and valiantly supported by 4 Corps Artillery (Brigadier A.A.K. Choudhry, Hilal-i-Juraat). The main effort of the Indian Army was blunted, inflicting heavy and troop casualties. Pakistan Air Force support helped turn the tide of the battle. Before a counter offensive by 6 Armoured Division on 22 September could be launched, Indian asked for cease-fire in the United Nations. India ‘s aggression against our international borders without a formal declaration of war had cost it, apart from heavy personnel, material land economic losses, 1617 sq. miles of territory as compared to 446 sq. miles of our open and undefended territory. Pakistan Army captured 20 officers, 19 Junior Commissioned Officers, and 569 Other Ranks.
(text from http://www.pakistanarmy.gov.pk/)