Sources said Wednesday that between 15 and 20 young British citizens have been training for a terrorism attack on Britain at al Qaeda camps in Pakistan. Britain and other European countries are on high terror alert after the CIA launched drone strikes in the Waziristan region of Pakistan in an attempt to thwart a possible Mumbai-style terrorist attack targeting Britain, France, and Germany. Sources in Pakistan said a missile from a unmanned U.S. drone in Pakistan killed several Britons. While intelligence officials are still researching the attack, sources said MI5 had traced it from Pakistan back to Britain. In response to the increased threat, British Metropolitan Police tactical response teams have been training on a “shoot to kill” basis after receiving briefings that said most deaths in this type of terrorist attack occur in the first 30 minutes.