A US drone fired two missiles into a Taliban base in Pakistan on Wednesday, destroying the compound and killing at least five militants, local officials said. The attack in the Baber Ghar area of the South Waziristan tribal district on the Afghan border, a stronghold of Taliban and Al-Qaeda-linked militants. "The target was a base of Pakistani Taliban. Five militants have been killed and two injured," a local security official told AFP. Another official in Wana, the main town in South Waziristan, confirmed the attack and told AFP the drone targeted a base of Pakistan's umbrella Taliban faction, Tehreek-e-Taliban. The covert strikes are publicly criticised by the Pakistani government as a violation of sovereignty but American officials believe they are a vital weapon in the war against Islamist militants. UN special rapporteur on counter-terrorism and human rights envoy Ben Emmerson, who visited Islamabad as part of an investigation into civilian casualties caused by drone strikes, said the US drone attacks violated Pakistan's sovereignty. According to Britain's Bureau of Investigative Journalism, CIA drone attacks in Pakistan have killed up to 3,577 people since 2004, up to 884 of them civilians.