A US drone strike has hit a compound in the Pakistani tribal region of North Waziristan, killing at least four people, security officials have said.
The strike took place in Degan area of North Waziristan on Saturday.
"US drones fired four missiles on a compound, killing four militants," a senior security official told the AFP news agency.
The official said several drones were flying in the area at the time of the attack. Another security official confirmed the strike and casualties.
The area has seen frequent drone activity in recent years, as the US has stepped up its campaign against suspected Taliban and al-Qaeda fighters in Pakistan.
The district is a stronghold of Hafiz Gul Bahadur, the leader of a local armed group, the security official said. He added that that fighters from the Haqqani group were also active in the area.
A drone strike a week ago in North Waziristan killed Badruddin Haqqani, one of the sons of the founder of the Haqqani network.
The US has blamed the group for a number of high-profile attacks in Afghanistan and considers it one of the key factors in undermining security there.
Badruddin was considered the organisation's day-to-day operations commander, and was labeled as a terrorist by the US State Department, along with his father and two of his brothers.
The US has demanded that Pakistan take action against the Haqqani group, while Pakistan has accused Washington of not targeting safe havens in Afghanistan that fighters use when launching attacks against Pakistan.
There has been a dramatic increase in US drone strikes in Pakistan since May, when a NATO summit in Chicago failed to strike a deal to end a six-month blockade on convoys transporting supplies to coalition forces in Afghanistan.
Islamabad and Washington have been seeking to patch up their fractious relationship in recent months, with the supply route reopening, after a series of crises in 2011 saw ties between the "war on terror" allies plunge.