Libyan authorities have made several arrests following the deadly attack on the US consulate in Benghazi, the Deputy Interior Minister has said.
American ambassador Chris Stevens and three of his staff were killed in Tuesday's assault.
President Obama vowed to do everything possible to protect Americans overseas as he honoured the four killed in the Libyan consulate attack.
Both Barack Obama and Mitt Romney know how they respond to the spread of violence across the Arab world could affect their election hopes.
Mitt Romney has attempted to score cheap, tawdry political points in the wake of the worst attack on the US diplomatic service in decades.