BEIRUT, Lebanon - At least three people were killed when an explosion hit a U.S. embassy vehicle in a Christian neighborhood of Beirut, security sources told Reuters on Tuesday.

The sources also said that a passenger of the diplomatic vehicle was wounded in the attack.

They said the blast was heard loudest in the Dora suburb in north Beirut. Smoke rose into the sky from a coastal road in the area.

Ambulances and security forces rushed to the scene, the witnesses said.

Lebanon has seen more than 30 explosions in the past three years, many targeting anti-Syrian politicians and journalists.

Last week a roadside bomb wounded two U.N. peacekeepers in southern Lebanon.