Islamabad - Six Islamic militants were killed by security forces in an overnight operation in northwestern Pakistan, while rockets fired by other rebels fell near the house of the chief minister of the region, officials said on Monday.

Troops killed the six insurgents on Sunday during a raid on a house in the Khazana area of the troubled Bajaur tribal district near the Afghan border, Major Murad Khan, a military spokesman, said.

The militants were disguised as personnel of the Frontier Corps (FC) paramilitary force which has been leading a major offensive against al-Qaeda and Taliban fighters in Bajaur since early August.

"The area from Rashakai and Loi Sam (villages) has been cleared by security forces," Khan said.

During their advance, the troops also came under rocket attack that was repulsed using tanks, artillery and mortar fire. Several militant strongholds used to engage the security forces were destroyed in the action, according to an FC statement.

Government forces have deployed jet fighters, helicopter gunships and artillery to pound the fortified positions of the rebels who the officials claims are getting assistance from their comrades battling foreign troops in Afghanistan.

Fierce clashes over the last two months have killed at least 1,000 rebels and more than two dozen troops, besides causing unknown number of civilian casualties.

The deteriorating situation, mainly attributed to illegal Afghan immigrants settled in the area, has forced the tribesmen to take up arms against the rebels. A three-day deadline given to the Afghans to leave Bajaur expired on Sunday.

Islamabad has pledged to tackle the militancy and terrorism in the tribal region head-on, and the nationalist government in the North-West Frontier Province (NWFP) has endorsed the strategy of using force to quell the violence.

The military action has triggered a spate of attacks on troops and senior governments officials in the north-western region.

On Sunday evening, rockets fired by suspected Islamist rebels landed near the family home of NWFP Chief Minister Amir Haider Khan Hoti in the town of Mardan.

The rockets damaged at least two house but not that of Hoti, who was in the provincial capital Peshawar at the time of the attack. No one was reported hurt in the incident.

The attack came three days after a suicide bomber blew himself up among a crowd greeting the chief of NWFP's ruling Awami National Party, Asfandyar Wali, in Wali Bagh village of Charsadda district. Wali escaped the assassination bid but five other people were killed.