The American ambassador to Libya and three other US diplomats were killed overnight in an attack on the American consulate in Benghazi by Islamist militants. Chris Stevens, who had completed several missions to Libya since 2007 and was appointed ambassador in March, was killed by a rocket-propelled grenade launched by gunmen from Islamist group, Ansar al Sharia, according to a Reuters report. -snip- The consulate was set on fire in the attack, while video footage of a lifeless Caucasian man thought to be Stevens, later appeared on YouTube.