A US missile strike by a drone killed at least five militants in Pakistan's North Waziristan tribal district on Monday, Pakistani security officials said.

The attack targeted militants sleeping at a compound in Haider Khel village of Mir Ali district in North Waziristan, 25 kilometres (15 miles) east of the region's main town of Miranshah.

"Five militants were killed," said a senior Pakistani security official on condition of anonymity.

"The drone fired two missiles," he added.

"The compound belonged to local tribesman Ahmad Ali and had become a hub of militants' movement," a local security official said.

The identities of those killed were not immediately clear, he added.

The United States considers the northwestern tribal region of Pakistan, which borders Afghanistan, a haven for Islamist militants who use the lawless area as a base to plan and carry out attacks on NATO and Pakistani forces.

The US has dramatically increased the frequency of drone strikes in the tribal belt in response to intelligence claims of a Mumbai-style terror plot to launch commando attacks on European cities.

More than 150 people have been killed since September 3, heightening tensions with Islamabad over reported US criticism of Pakistan's failure so far to launch a ground offensive in North Waziristan.

The United States does not as a rule confirm drone attacks, but its military and the Central Intelligence Agency operating in Afghanistan are the only forces that deploy the pilotless aircraft in the region.

Officials in Washington say drone strikes are highly effective in the war against Al-Qaeda and its Islamist allies, killing a number of high-value targets, including the Pakistani Taliban's founding father Baitullah Mehsud.

But the policy is unpopular among the Pakistan public who see military action on Pakistani soil as a breach of national sovereignty.

It has led to reprisals from militant groups who have targeted NATO supply convoys destined for Afghanistan.