Grenade attack in Pakistan's Waziristan kills 3

PESHAWAR, Pakistan, May 20 (Reuters) - Pro-Taliban militants killed two Pakistani troopers in a grenade attack on a paramilitary compound in North Waziristan, but one of their own men was also killed, a government official said on Saturday.

A military campaign to clear foreign militants from tribal lands near the Afghan border and subdue their Taliban allies is focused on North Waziristan. Fighting there has intensified over the past few months.

Fida Mohammad, a senior administration official in the region, said three militants threw grenades at the Frontier Constabulary compound in Mir Ali town, 25 km (15 miles) east of Miranshah, the main town in North Waziristan.

Two members of the force and one of the attackers were killed, he said.

"Two attackers managed to escape but one died in the attack as he slipped when he started running away after throwing the grenade," Mohammad said.

Many al Qaeda militants and their Taliban allies took refuge among Pakistan's conservative Pashtun tribes on the border after being driven out of Afghanistan by U.S.-backed forces following the Sept. 11, 2001, attacks on the United States.

Following the attack on the compound, helicopter gunships circled over Mir Ali and fired rockets, residents said. It was unclear to residents who they were firing at, or if there were casualties.

Security forces have killed over 300 militants, including about 75 foreigners, in North Waziristan since the middle of last year, official say.