BEIRUT, Lebanon (AP) – A small explosion damaged a car in south Beirut Saturday and injured a woman who was passing by, police said.

Explosive experts were trying to learn whether the explosion was caused by a bomb wired to the car or had been placed under it.

The woman suffered minor injuries, the police said. Lebanon has witnessed a series of mysterious bombings since a massive truck bomb killed former Premier Rafik Hariri and 20 others on Feb. 14, 2005. In 14 bombings since then, 11 people were killed.

The last explosion was Feb. 2, which injured a soldier when a bomb was tossed at the wall of a Beirut army barracks.

The explosion in the predominantly Shiite Muslim area of Ouzai as tension and apprehension increased in the Lebanese capital in the days before massive demonstrations were expected to mark the first anniversary of Hariri’s assassination.

Six days ago, Muslim extremists participating in a protest against Danish cartoons rioted in a Christian neighborhood and clashed with police, setting fire to the building housing the Danish mission and raising sectarian tensions.

Christian and Muslim politicians and spiritual leaders have called for calm.