Pakistan has been trying to clear militants from its lawless tribal areas on the border since early last year. Hundreds of militants and Pakistani soldiers have been killed.

The latest round of clashes began last week.

In the first attack on Sunday, militants firing rockets launched a pre-dawn raid on a paramilitary check-post near the town of Miranshah in the troubled North Waziristan tribal region, 400 km (250 miles) southwest of the capital, Islamabad.

"The rockets were fired from a nearby mountain ... two soldiers were killed and four wounded," said a security official, who declined to be identified.

Many al-Qaeda militants and their Taliban allies were believed to have slipped into Pakistan after US-led forces ousted the Taliban government in Afghanistan in the wake of the Sept. 11, 2001, attacks on the United States.

Pakistani forces, backed by helicopter gunships, launched a fresh offensive in North Waziristan on Thursday and at least seven Pakistani soldiers have been killed since then.