Four people have been arrested by Libyan authorities following the attack on the US consulate in Benghazi in which the US ambassador and three embassy staff were killed.
Deputy interior minister Wanis Sharif told Reuters:
Four men are in custody and we are interrogating them because they are suspected of helping instigate the events at the US consulate.
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.