A suspected U.S. strike killed six people on the Pakistan side of the Afghan border, a lawless region believed to be a stronghold of Al Qaeda, two intelligence officials said.

The identities of those killed in the attack Thursday was not immediately known, the officials said on condition of anonymity because they were not authorized to speak to the media.

"At present, local Taliban have surrounded the destroyed house, and they are not letting anybody get close to it," said one of the officials.

Citing agents and informants in the field, the officials said six people were killed in the strike late Thursday in a village near Azam Warsak in South Waziristan.

The United States is suspected of carrying out more than 30 missile strikes against militant targets on the Pakistan side of the Afghan border since August.

The attacks have killed scores of militants, but angered Pakistani leaders, who say they undermine their own war on terror.

Most of the missiles are believed launched from unmanned spy planes that take off from neighoring Afghanistan.

Washington rarely confirms or denies the attacks. However, the U.S. military has said that the Taliban and other radical Islamist groups based on the Pakistan side of the border carry out attacks on American troops in Afghanistan.