Unknown gunmen fired a rifle grenade at a police garrison in Beirut Wednesday night, causing minor material damage but no casualties, security sources said.

The grenade exploded at the surrounding of Helou barracks in Mar Elias street shortly after night fall, the sources said, adding police deployed around the barracks after the incident.

Earlier, Qatar-based al-Jazeera TV channel reported that an explosion were heard on Wednesday night in a Beirut neighborhood near a major police barracks.

The grenade attack took place amid heightened tensions between pro-Syrian Hezbollah, or Party of God, and the government's anti- Syrian majority.

The Helou police station sustained a similar attack nearly three weeks ago as part of a series of assaults aimed at destabilizing the security situation in Lebanon.

A total of four similar security incidents took place in Beirut last month, which targeted two police barracks, a downtown commercial building and an affluent neighborhood that houses the residences of ambassadors from Saudi Arabia and the United Arab Emirates (UAE).

The attacks prompted the government earlier this month to tighten security in the capital and install security cameras in public areas of downtown Beirut and its suburbs.

Source: Xinhua