Three missiles fired by US drone aircraft killed five militants on Monday in Pakistan's northwest tribal belt, a bastion of Taliban and Al-Qaeda-linked fighters, security officials said.

The latest in a series of US drone attacks targeted militants in the centre of Miranshah, the main town of North Waziristan, a rebel stronghold near the Afghan border.

"Five people have been killed and three wounded in the attack. It was an American drone attack," an intelligence official in Miranshah told AFP by telephone.

A security official in Peshawar confirmed the strike saying missiles from two drones hit a compound in Miranshah, while residents said the missiles struck two different buildings close to each other in the main bazaar.

"I was in the mosque when I heard three huge explosions. The electricity was disconnected after the explosions," one resident told AFP by telephone requesting anonymity.

"Two drones fired three missiles in Miranshah bazaar. Two buildings in the centre of the bazaar were hit and destroyed in the attack," he added.

A US drone strike in Miranshah in February killed Mohammed Haqqani, a brother of Al-Qaeda-linked warlord Sirajuddin Haqqani, whose network is fighting against US and local forces in neighbouring Afghanistan.

Officials in Washington have hailed the drone campaign for eliminating a number of high-value targets in terrain classified as an intelligence black hole and which Al-Qaeda has turned into its global headquarters.

The covert US drone war against Al-Qaeda and Taliban leaders has focused increasingly on North Waziristan, a bastion of multiple militant groups, since a December 30 suicide attack killed seven CIA employees in Afghanistan.

North Waziristan borders Khost province, where a Jordanian doctor turned Al-Qaeda double agent blew himself up in the deadliest attack on the US spy agency in 26 years.

US officials, who never confirm the drone strikes, increasingly believe that Hakimullah Mehsud, leader of the Pakistani Taliban, perished in a US attack in January.

However, there has been no official confirmation from the Pakistani government and the Pakistani Taliban insist he is alive.

His predecessor Baitullah Mehsud was killed in a similar attack in August.