ISLAMABAD (AP) Three suspected militants blew themselves up as police gave chase Saturday in the Pakistani part of disputed Kashmir, authorities said.

No other casualties were reported, but the incident underscored fears that militants are preparing attacks in other areas as retaliation for an army offensive under way in the Afghan border region of South Waziristan. The Pakistani military said Saturday that 14 militants and six soldiers were killed over the last 24 hours as part of that operation.

The three men in Kashmir fled after police acting on a tip raided their hide-out in the Thori area of regional capital Muzaffarabad, according to senior police officer Sardar Ilyas.

Police pursued them and the men detonated explosives on their bodies after being trapped on a mountain, Ilyas said, adding 18 hand grenades, three assault rifles and a pistol had been seized from the hide-out.

Security was tightened around government buildings and other potential targets in the city amid fears of violence, Ilyas said.

Kashmir is disputed between Pakistan and India, who both claim the territory in its entirety. The two nuclear rivals have fought two wars over the region since gaining independence from British rule in 1947.

In northwestern Pakistan, a gas explosion injured one person and damaged a two-story building Saturday in Peshawar. Police initially said it was a bomb but later determined it was an accident.

The conflicting statements reflect the atmosphere of fear that has taken hold in Peshawar, the largest city in the northwest and the main gateway to the al-Qaida and Taliban-infested frontier region. Violence has increased in the area since the army launched the operation in nearby South Waziristan in mid-October. Many militants are believed to have fled the fighting.

Senior officers, including the city's police chief, first said the explosion, which partially destroyed the two-story building, was caused by a bomb.

But Haroon Babar, a senior police officer, said a bomb disposal squad sent to the site found no explosives.

''It seems that a gas pipeline under the wall might have exploded causing the damage,'' he said.

Pakistan helped nurture a generation of Islamic militants after the Soviet Union invaded Afghanistan in 1979. Following the Soviet withdrawal a decade later, Pakistan helped the Taliban seize control. Many of these militants fled to Pakistan after the U.S.-led invasion of Afghanistan in late 2001.