Updated

A suspected U.S. drone fired two missiles at a house in Pakistan's northwest tribal region near the Afghan border Thursday, killing six people, Pakistani intelligence officials said.

The attack occurred in Spalga village in the North Waziristan tribal area, the main sanctuary for Taliban and Al Qaeda militants in Pakistan, said the officials, speaking on condition of anonymity because they were not authorized to talk to the media. The identities of those killed were unknown.

A salvo of U.S. missiles hit a house in Spalga about a week ago as well, killing nine people, including some Pakistani Taliban militants, intelligence officials said.

The area is dominated by Hafiz Gul Bahadur, a prominent militant commander focused on fighting foreign troops in Afghanistan.

President Barack Obama has significantly ramped up drone attacks in Pakistan since he took office. He recently acknowledged the covert CIA-run program in Pakistan for the first time in an interview. But he and other U.S. officials refuse to discuss details of the program openly.

Pakistani officials regularly denounce the strikes as a violation of the country's sovereignty, but the government is widely believed to have provided support for the program in the past.