A US drone strike killed four suspected militants on Sunday in a north-western tribal region in Pakistan along the Afghan border, intelligence officials and Taliban fighters said.

Those killed included two Arab militants and two of their local allies in a compound in the town of Wana in South Waziristan, the two officials and three Taliban fighters said.

All of them spoke on condition of anonymity because they were not authorised to talk to journalists. Authorities don’t allow journalists into Pakistan’s tribal areas, which have long been a safe haven for local and al-Qaida linked foreign militants.

Pakistan’s army largely cleared militants from South Waziristan in a 2009 operation, but militants still maintain a presence in its pockets, especially in its rugged terrain and thick forests.

Soldiers and Pakistan’s air force now are fighting militants in North Waziristan in an operation that began in June.

US drone strikes are widely unpopular in Pakistan, where many consider them a violation of the country’s sovereignty that also killed civilians. But Washington has long relied on them to take out the militants in areas where Pakistan’s army won’t deploy.

The US does not comment on the strikes, which are carried out by the CIA.

On 24 September, a suspected American drone strike killed 10 alleged militants in the region that is also home to Afghan militant groups, including the Haqqani network, which attacks US and allied Nato troops in Afghanistan.

The Pakistani Taliban also has strong presence in the tribal areas. It has been waging a war on the state in a bid to overthrow the government and install their own brand of harsh Islamic law, killing tens of thousands of people.