MIRANSHAH, Pakistan - Around 150 militants armed with rockets attacked a security checkpost in Pakistan's Waziristan on Thursday, killing eight soldiers, intelligence officials said, as tensions rise in the volatile northwestern region along the Afghan border.

The attack, in which about 12 militants were killed, appeared to be part of a new strategy by the Pakistani Taliban of staging large-scale attacks on military and government targets in a bid to demoralise the army.

The attack came on the heels of stepped-up missile strikes by US drone aircraft in the tribal region along the Afghan border regarded as a hub of militants from around the world.

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The Pakistani Taliban have intensified attacks across Pakistan in recent weeks to avenge the killing of Osama bin Laden by US special forces in the country on May 2.

The United States appears to have intensified its drone missile strikes against militants, especially after a US Secretary of State Hilary Clinton visited Pakistan recently and urged Pakistan to do more to fight insurgents.

It's not clear if Pakistan, recipient of billions of dollars in American military aid, has shared intelligence with the Americans in stepped up drone missile attacks in South Waziristan. The CIA, which operates the remotely-piloted drones, may have spotted high-value al Qaeda or Taliban militants in the area.

No one claimed responsibility for Thursday's militant attack on the military post. Last week, the Pakistani Taliban attacked a checkpost in the northwest, and officials said up to 400 militants took part.

"The militants were carrying rockets and heavy weapons and attacked the checkpost shortly after midnight," an intelligence official in Waziristan told Reuters, describing the latest attack. "Eight soldiers were killed and twelve were wounded."

Security forces hit back, killing at least 12 militants, another official said. It was not possible to verify the casualty figures. The attack took place on the border between North and South Waziristan.

Army offensives have failed to break the back of militants. On Thursday, a bomb went off in a market near the northwestern city of Peshawar, killing four people and wounding three, hospital officials said.  

Intelligence officials say there has been an escalation of strikes in South Waziristan because militants have been moving there following speculation that the army plans an offensive in North Waziristan. Militant commanders there deny that.  

Pakistani army officials say there are no plans for an imminent offensive in the north.

Drone strikes are pounding areas of South Waziristan controlled by a militant group that is not opposed to the Pakistani state and is not attacked by the army.

Its operations are limited to cross border assaults on US-led NATO forces in Afghanistan, where the United States plans in July to start withdrawing some of its forces fighting a 10-year war against the Taliban.