An official and witnesses in Libya's capital say random shells fired by rival militias fighting for control of its international airport hit oil depots, setting them ablaze after a massive fire last month.

The weekslong violence in Tripoli and in Libya's second-largest city of Benghazi have killed more than 200 people and wounded almost 900. The violence has forced diplomats to flee and close their embassies while foreign nationals and Libyan citizens streamed into neighboring Tunisia searching for safety.

A Libyan official at the National Safety Agency, who spoke on condition of anonymity because he was not authorized to speak to journalists, said the oil depots caught fire Saturday after three others caught fire last month.

Tunisia also opened its main border crossing with Libya after brief closure Friday.