BEIRUT (Reuters) - At least three people were killed in an explosion in Beirut on Tuesday which wounded a passenger in a diplomatic car, security sources said, and Lebanon's LBC television channel said a U.S. embassy car was hit.

Security sources said the explosion occurred in a Christian neighborhood of Beirut.

Witnesses said ambulances rushed to the scene, as smoke rose into the sky.

The blast was heard loudest in the Dora suburb in north Beirut, the sources and 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.

(Reporting by Nadim Ladkil; Editing by Caroline Drees)