Suspected U.S. missiles killed four people on the Pakistani side of the Afghan border on Friday, the sixth such strike in the militant-held area in just over a week, according to AP. The attack took place in North Waziristan, which is the stronghold of the Haqqani network, an Afghan Taliban group with links to al-Qaida. Its militants are responsible for cross-border attacks on American troops and could have played a role in the Dec. 30 attack that killed seven CIA employees in Khost province, just across the frontier. The U.S. does not comment on the strikes or their targets. It has carried out more than 50 of them since last year, most by unmanned planes believed operated by the CIA with the cooperation of Pakistani intelligence. They have been more common since President Barack Obama took power. Two Pakistani intelligence officials said a pair of missiles Friday evening hit a house and a vehicle in a village near Miran Shah in North Waziristan. They said four people were killed and three injured. They did not identify them. The officials spoke on condition of anonymity because they were not authorized to release the information to media. Pakistan"s government publicly condemns the drone strikes as violations of its sovereignty. One attack in August killed Baitullah Mehsud, the leader of the Pakistani Taliban, which have been leading a deadly insurgency against the Pakistani government from their sanctuary in the tribal areas.