US Secretary of State Hillary Clinton said on Tuesday she accepted the findings of an independent panel that faulted the State Department over the deadly September attack on the US mission in Benghazi, Libya.

Clinton said she had ordered widespread changes to bolster US diplomatic security overseas. In a letter to US congressional committees, she said she had instructed the State Department to implement its findings "quickly and completely".

Clinton also outlined a series of steps aimed at improving the security of US diplomatic outposts.