Tension flares between India, Pakistan

NEW: India says Pakistan started firing first Indian soldiers crossed the Line of Control on Sunday morning, Pakistan says Pakistan says one of its soldiers is critically injured (CNN) -- Tensions between India and Pakistan flared Sunday in the Kashmir region, with at least one Pakistani soldier killed in the violence, its military said. But exactly what happened depends on the source. According to the Pakistani military, Indian troops crossed the Line of Control -- the de facto border between India and Pakistan in the disputed Kashmir region -- and attacked a military post. "Pakistan Army troops effectively responded and repulsed the attack successfully," but one Pakistani soldier was killed and another critically injured, the military said. The Indian Defense Ministry, however, said Pakistani troops opened fire unprovoked on Indian posts in the north Uri sector of Indian-administered Kashmir. Indian troops retaliated and forced Pakistani troops to stop firing, the defense ministry said. The ministry did not immediately report the number of casualties, but said three civilians were killed by Pakistani shelling in the area last October. The territory under dispute lies in India's Kashmir Valley, separated from Pakistan by the 450-mile Line of Control. The two south Asian nuclear neighbors have had a bilateral ceasefire along the de facto border since November 2003. But the ceasefire has been violated repeatedly, with both sides accusing each other of offenses. Bilateral talks were temporarily suspended in 2008 following an attack by Pakistani militants in Mumbai, India's most populous city. The negotiations resumed last year. The conflict dates back to 1947 after Britain relinquished control of the Indian subcontinent, giving birth to India and Pakistan. Kashmir was free to accede to either nation. Maharaja Hari Singh, the ruler of the kingdom at the time, initially chose to remain independent but eventually opted to join India, thereby handing key powers to the central government in New Delhi. In exchange, India guaranteed him military protection and vowed to hold a popular vote on the issue. The South Asian rivals have fought two of three wars over the territorial issue -- in 1947 and in 1965. A third conflict between India and Pakistan erupted in 1999 after Pakistani-backed forces infiltrated Indian-controlled Kashmir in the Kargil area. Islamabad has always maintained that majority-Muslim Kashmir should have been a part of Pakistan. A United Nations' resolution adopted after the first war called for a referendum allowing the people of Kashmir to choose which country they wanted to join, but that vote for self-determination has never been held. Pakistan wants that referendum to take place. India claims that Pakistan lends support to separatist groups fighting against government control and argues that a 1972 agreement mandates a resolution to the Kashmir dispute through bilateral talks. if(typeof CNN.expElements==='object'){CNN.expElements.init();} Mukhtar Ahmad reported from Srinagar, India; Shaan Khan reported from Islamabad, Pakistan. CNN's Nasir Habib also contributed to this report.