The US has for the first time outlined when it will kill Americans who are plotting attacks against the country.
US Attorney General Eric Holder said American citizens living abroad could legally be targeted with "lethal force" if there was an imminent threat.
The Obama administration was criticised by civil liberties groups after it killed the US-born Islamist cleric Anwar al-Awlaki in September 2011.
But Mr Holder said the US was "at war", so court approval was not needed.
'Threat justifies force' In a speech at the Northwestern School of Law in Chicago, he said use of lethal force would be governed by the laws of war, but sometimes the government had to act quickly, making it impractical to seek permission from a court.
"Military and civilian officials must often make real-time decisions that balance the need to act, the existence of alternative options, the possibility of collateral damage, and other judgements," said Mr Holder.
"All of which depend on expertise and immediate access to information that only the Executive Branch may possess in real time."
BBC
US Attorney General Eric Holder said American citizens living abroad could legally be targeted with "lethal force" if there was an imminent threat.
The Obama administration was criticised by civil liberties groups after it killed the US-born Islamist cleric Anwar al-Awlaki in September 2011.
But Mr Holder said the US was "at war", so court approval was not needed.
'Threat justifies force' In a speech at the Northwestern School of Law in Chicago, he said use of lethal force would be governed by the laws of war, but sometimes the government had to act quickly, making it impractical to seek permission from a court.
"Military and civilian officials must often make real-time decisions that balance the need to act, the existence of alternative options, the possibility of collateral damage, and other judgements," said Mr Holder.
"All of which depend on expertise and immediate access to information that only the Executive Branch may possess in real time."
BBC