One of the likeliest flash points for a nuclear war is the enduring conflict between India and Pakistan, which have scores of nuclear weapons. In recent weeks, several fatal incidents across the disputed Kashmir border have stoked new fears that the firing of bullets could escalate into something even worse.

The latest conflict began on Jan. 6 when Pakistani and Indian troops exchanged gunfire across the Kashmir border, leaving one Pakistani soldier dead. Two days later, another confrontation resulted in the deaths of two Indian soldiers, one of whom was beheaded. A third incident occurred on Jan. 10 when the Pakistani Army said that Indian soldiers shot and killed a Pakistani soldier. On Wednesday, Pakistan accused India of killing another of its soldiers, making the past two weeks the worst for violence in the Kashmir region since a cease-fire was reached in 2003.

Prime Minister Manmohan Singh of India, who has advocated rapprochement with Pakistan, said this week that the recent hostilities had made a continued thaw in relations impossible. And India’s new army chief, Gen. Bikram Singh, has threatened to retaliate for the killings of the Indian soldiers. He said at a news conference on Monday that he had directed his military commanders to be “aggressive” in the face of provocations. For its part, Pakistan has dismissed India’s charges and accused it of violating the line of control in Kashmir.

The confrontations are especially disturbing because India and Pakistan, which have fought three wars, have made some progress in their relationship over the past year, allowing more travel across the border and better trade ties. Both countries face huge challenges, including the need for economic growth, and neither can afford another war.