The US has resumed its drones programme in Pakistan, with two strikes on militant strongholds in the North Waziristan tribal region overnight.
Officials say at least three militants were killed with reports of 16 dead.
It comes days after militants attacked Karachi international airport, killing 39 people, including 10 attackers.
Washington agreed to suspend its drones programme in December to allow Islamabad to pursue peace talks with the Pakistani Taliban (TTP).
But pressure has been mounting on the Pakistani authorities to launch a ground offensive on the region amid a breakdown in peace talks.
After an initial strike at 20:30 local time (15:30 GMT) on Wednesday evening, the same area was hit in the early hours of Thursday morning.
"Three US drones fired six missiles on militants who had gathered to dig the debris of a compound," a security official told the AFP news agency, referring to the compound destroyed in the earlier drone strike.
Pakistan's Geo News reports that as many as 16 people were killed in the two attacks.
Internally displaced Pakistanis arrive in Bannu, a town on the edge of Pakistan's lawless tribal belt of Waziristan, on 11 June 2014.
Officials say some of those killed in the first attack were Uzbeks and local Taliban members, according to the AFP news agency.
On Wednesday, Uzbek militants of the Islamic Movement of Uzbekistan (IMU) claimed to have carried out the attack on the airport, saying it was in retaliation for military air strikes.
The group, which is highly-trained and has bases in North Waziristan, has previously carried out large-scale co-ordinated attacks with al-Qaeda and Taliban militants in Pakistan.
Washington uses unmanned drones to carry out strikes on Taliban and al-Qaeda targets in Pakistan's border region with Afghanistan.
However, US strikes have not taken place since 25 December 2013 in response to calls by Pakistan to halt strikes and enable peace negotiations.
Pakistan launched air strikes against Pakistan's north-west Khyber region, killing at least 15 militants.