President Barack Obama and Libyan President Mohamed Magarief spoke on Wednesday evening, agreeing to investigate the attacks on the US consulate in Benghazi, according to the White House.
"The (US) President made it clear that we must work together to do whatever is necessary to identify the perpetrators of this attack and bring them to justice. The two presidents agreed to work closely over the course of this investigation," the White House said in a statement.
Protests on Sept. 11 over a US film featuring the Prophet Mohammed turned deadly in Benghazi, claiming the lives of the ambassador and staff.
Obama also called Egyptian President Mohamed Morsi about the protests in that country and said Egypt "must cooperate with the United States in securing US diplomatic facilities and personnel," the White House said.
"The President said that he rejects efforts to denigrate Islam, but underscored that there is never any justification for violence against innocents and acts that endanger American personnel and facilities," it also said.