A US drone attack on a militant compound in Pakistan's northwest tribal area Thursday killed five militants including three Arabs, security officials said.

Two missiles were fired on the compound in Ismail Khel village, about 40 kilometres (25 miles) west of Miranshah, the main town in the North Waziristan region bordering Afghanistan, they said.

"The target was a militant compound," one official said. "Three Arabs, one Afghan and one local were killed in the attack."

Another official said: "At least two others were injured in the attack."

It was not immediately clear if the casualties included any high-value targets, officials said.

The region is considered a stronghold of militants linked to the Taliban and Al-Qaeda who are involved in attacks on US and NATO forces fighting the Islamist insurgency across the border in Afghanistan.

US drone strikes killed up to six militants in Pakistan's tribal belt on Wednesday, targeting the extremist Haqqani network and a compound harbouring foreign fighters, officials said.

Pakistani security officials said two militants were killed and one wounded in a pre-dawn drone attack on a house in the Spinwam area in Mir Ali district, 30 kilometres (19 miles) northeast of Miranshah.

Hours later, a Pakistani security official said a drone strike killed three militants in the Degan area of Datta Khel district, 35 kilometres (22 miles) west of Miranshah.

"They were from the Haqqani network," the senior security official said on condition of anonymity.

Another official put the death toll at four, including two foreigners.

The covert US drone campaign stepped up strikes in Pakistan's tribal belt on the Afghan border last month over intelligence claims of a Mumbai-style terror plot to launch attacks on European cities.

Around 35 such attacks since September 3 have killed more than 185 people, according to an AFP toll. Around 150 drone strikes since August 2008 have killed more than 1,200.

The United States considers Pakistan's tribal belt an Al-Qaeda headquarters, and Western officials say the drone campaign is seen as integral to US-led efforts to beat back a nine-year Taliban insurgency in Afghanistan.