A small explosion rocked the Egyptian consulate in the Libyan city of Benghazi this afternoon, blowing out its windows and those of adjacent buildings, witnesses said.

A policeman at the scene said an Egyptian security guard was injured in the explosion, apparently caused by a small bomb hidden in a briefcase. At least five cars were damaged, a Reuters witness said.

Police closed off the area and were collecting evidence.

Egyptian security forces are conducting a crackdown on Muslim Brotherhood supporters following last month's ousting of Islamist President Mohamed Mursi.

U.S. ambassador Christopher Stevens and three other Americans were killed in Benghazi last year after Islamist gunmen attacked the U.S. consulate during a protest by a mob angry over a film they said insulted the Prophet Mohammad.