US may kill its nationals involved in terror acts overseas

US forces and agencies may kill American citizens abroad if they are found to be involved in terrorist activities overseas, a top US official has said.     "We take direct action against terrorists in the intelligence community. If that direct action ... will involve killing an American, we get specific permission to do that," Dennis C Blair, director of National Intelligence said in his testimony before the House Intelligence Committee.     "We don't target people for free speech. We target them for taking action that threatens Americans," he said in response to a question from members.     Blair told the Committee that he was speaking publicly about the issue to reassure Americans that intelligence agencies and the department of defence "follow a set of defined policy and legal procedures that are very carefully observed" in the use of lethal force against US citizens.     His unusually frank remarks comes as instances are growing of American nationals taking part in terrorist activities overseas, which subsequently threatens US security itself.