Missiles fired from a US drone on a vehicle and a house killed five militants in Pakistan's lawless northwestern tribal belt near the Afghan border on Monday, security officials said.

The missile strike took place in Khysore village, 35 kilometres (20 miles) east of Miranshah, the main town of troubled North Waziristan tribal district.

"A US drone fired four missiles on a house and a vehicle," a senior Pakistani security official told AFP. "At least five militants were killed."

A local intelligence and security official confirmed the strike and casualties.

"First the US drone fired two missiles on a militant vehicle and two of the occupants were killed, while three others escaped and hid in a shop adjacent to a house.

"The drone fired two more missiles on the shop and three of them were killed and three others were wounded," the official said.

A covert US drone campaign in Pakistan has been stepped up over the last few months with strikes in the tribal belt, which Washington considers the most dangerous place on earth, taking place with increasing frequency.

More than 250 people have been killed in 49 strikes 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 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.

The leadership of the Haqqani network, which is linked to the Taliban and Al-Qaeda, is also based in North Waziristan.

It has been accused of plotting some of the deadliest attacks on US troops in Afghanistan, including a suicide bombing that killed seven CIA operatives at a US base in Khost last December.

Pakistan's foreign ministry said recently it would reject any overtures seeking to spread the drone campaign beyond the tribal areas, amid US press reports that Washington wanted to expand the zones inside Pakistan where the pilotless aircraft are allowed to operate.

The Pakistani Taliban have claimed responsibility for a number of arson and gun attacks on NATO supply convoys destined for Afghanistan, saying they are in revenge for the drone war.

Washington has attempted to soothe anti-Americanism, which is rife throughout Pakistan, with increased civilian aid to help the country overcome devastating summer floods.