A missile strike, reportedly by a U.S. drone, killed 15 people in South Waziristan Monday, officials reported. The home of a widely recognized Taliban supporter was the target, marking the third attack in four days against the militant sanctuary. The U.S. has "stepped up" the pace of drone attacks in response to the suicide bomber who killed seven CIA agents in December, The Washington Post reports. Not all of the attacks have been successful. Top Taliban leader Hakimullah Mehsud survived Thursday's attack, but is rumored to be injured.