A drone attack on a suspected militant compound killed at least 20 in South Waziristan early Sunday morning, Pakistani officials said.
The drone fired at least four missiles at the compound in the village of Nizba, a restive tribal area bordering Pakistan, the officials said.
It was the third drone strike targeting the Shaktoi region in the past four days.
The United States is the only country in the region known to have the ability to launch missiles from drones, which are controlled remotely.
U.S. officials normally do not comment on suspected drone strikes, which have caused tension between Pakistan and the United States in the past.
Sunday's attacks follows one on Thursday that intelligence officials said wounded Hakimullah Mehsud, the leader of the Taliban in Pakistan.
The Taliban responded by releasing two audio tapes said to be from Mehsud in which he said he was in good health.
"Neither have I been martyred in a drone attack nor injured," the voice says on a tape released on Saturday. CNN could not confirm whether the voice was that of Mehsud.
A Taliban spokesman, Azam Tariq, said Mehsud had left the site of the attack -- a converted religious school -- before the missiles struck.

The house targeted in Sunday's attack was being used by Usman Jan, the head of the al Qaeda-linked Islamic Movement of Uzbekistan, intelligence officials said. Five Uzbeks were killed in the strike, but it was unclear if Jan was among them. Jan's predecessor, Tahir Yuldash, was killed in a drone strike in South Waziristan last year. The other 15 people killed in Sunday's strike were Pakistani Taliban, said the officials. The U.S. does not usually comment on the drone strikes or their targets, but officials have said in the past that they have taken out several senior al Qaeda and Taliban leaders.

The drone program is completely out of control ,even Bush didn't promote it. No arrest , no trial ,hardly any ID on the victims in a foreign nation where we are not even at war. Sold to the Pentagon and Obama by defense corporate insiders.