Explosion Rocks Hezbollah Stronghold in Beirut

Blast also reported in Damascus; Syrian website Al-Hakika reports Friday's attacks on arms depot in Damascus targeted advanced Yakhont land-to-sea missiles.

A large explosion rocked a stronghold of the Shiite militant Hezbollah group in the Lebanese capital early Tuesday, sending black smoke billowing into the sky and causing an unknown number of casualties, security officials said.

The officials said it was not clear whether the blast in the suburb of Beir el-Abed in south Beirut was caused by a car bomb. The officials, who spoke on condition of anonymity in line with regulations, said it was near a gas station.

Also on Tuesday, Al Arabiya reported that a huge explosion rocked central Damascus overnight, in the al-Baramika area.

Report of the blast come days after a series of explosions in the Syrian military's arms depot in port city of Latakia, an Alawite stronghold in the north of the country along the Mediterranean coast. After initials news of the blasts Thursday night, reports differed on their source.

According to the Syrian website Al-Hakika, the attack on the arms depot destroyed a cache of Yakhont land-to-sea missiles. Such missiles are capable of hitting targets at sea at a distance of up to 300 kilometers carrying a 250-kilogram warhead. Russia had supplied Syria with a 72 Yakhont missiles a year and a half ago, and plans to also supply the country with an advanced radar system to improve their accuracy.

The New York Times reported two months ago that according to officials in Washington, D.C., the new Russian shipment has already reached Syria. The Yakhont is a considered an accurate and devastating weapon that poses a threat to Israel's maritime traffic, as well as its infrastructure on the coast.

Hezbollah's Al-Manar TV said Tuesday's blast in Beirut was caused by a car bomb inside a parking lot near an Islamic center. The station broadcast footage of a thick plume of smoke rising into the sky at the site of the blast as people rushed to take casualties to the hospital.

Some Syrian rebel groups have threatened to strike in Lebanon after Hezbollah joined Syrian President Bashar Assad's troops in their battle against opposition fighters.

In May, two rockets slammed into a Hezbollah stronghold in south Beirut, wounding four people. The rockets struck hours after Hezbollah leader Sheikh Hassan Nasrallah vowed in a speech to help propel Assad to victory in Syria's civil war.

Hezbollah has openly joined the fight in Syria, and the group's fighters were instrumental in a recent regime victory when government forces regained control of the strategic town of Qusair near the Lebanese border.