WASHINGTON (Reuters) - US military surveillance drones have resumed tracking militants in Pakistan to support Pakistani operations against Taliban insurgents in the South Waziristan region, officials said on Thursday. The officials, who spoke on condition of anonymity, said the drones provide Pakistan with video images, communications intercepts and other information from border areas controlled by Pakistani Taliban leader and Al-Qaeda ally Baitullah Mehsud. The flights are not connected with US missile attacks from CIA drones, which the Pakistan government has condemned. Suspected US missile strikes killed more than 40 fighters in South Waziristan on Wednesday, according to security officials. The US military began surveillance flights over Pakistani territory in mid-March but ceased a month later when Pakistan abruptly stopped requesting the intelligence. Officials said the missions resumed early last month. The Pakistan army is preparing an offensive against Mehsud, who officials blame for 90 per cent of terrorist attacks in Pakistan. Pakistan already has taken some action, including air strikes against Mehsud targets last month. US military officials accuse Mehsud of providing suicide bombers for insurgent attacks against US, NATO and Afghan targets in Afghanistan. The militant leader also is accused in the 2007 assassination of former Prime Minister Benazir Bhutto. US military officials first confirmed the drone surveillance programs existence in May. The Pentagon views the missions as a way to aid Pakistan while extending its own surveillance of militant safe havens that threaten US and NATO forces in Afghanistan