A car bomb has rocked a stronghold of the Shiite militant Hezbollah group in Beirut wounding dozens in a major security breach of a tightly-guarded area.
The powerful blast in a bustling commercial and residential district came as many Lebanese Shiites began observing the holy month of Ramadan, and is the worst explosion to hit the area in years - likely direct fallout of the civil war raging in neighbouring Syria.
A group of about 100 outraged Hezbollah supporters marched in the area after the blast, carrying pictures of Hezbollah chief Sheik Hassan Nasrallah and shouting in support of their leader and sectarian slogans.
Hezbollah gunment fired in the air to disperse people who attacked the interior minister with stones after he inspected the scene of the blast, trapping him for 45 minutes in a building before he was escorted through a back door. Marwan Charbel is seen by some Shiites as sympathetic to hardline Sunni cleric Ahmad al-Assir, who was agitating against Hezbollah for months and is now on the run.
With skirmishes between Shiites and Sunnis on the rise around the country, religiously mixed and dangerously fragile Lebanon is increasingly buffeted by powerful forces that are dividing the Arab world along sectarian lines. Some Syrian rebel groups, which are predominantly Sunni, have threatened to strike in Lebanon after Hezbollah joined Syrian president Bashar Assad's troops in their battle against opposition fighters.
The explosion struck the area of Beir el-Abed in a car park near the Islamic Coop, a supermarket usually packed with shoppers, and a petrol station.
The area is a few hundred yards from what was known as Hezbollah's "security square" where many of the party's officials live and have offices. Nasrallah received dignitaries there before the 2006 war. The so-called security square was bombed out by Israel in that conflict and Nasrallah has gone underground since then, only rarely appearing in public and never for more than few minutes, fearing Israeli assassination.
In May two rockets slammed into a Hezbollah stronghold in south Beirut, wounding four people. The rockets struck hours after 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 was instrumental in a recent regime victory when government forces regained control of the strategic town of Qusair near the Lebanese border.
Lebanon's Sunni Muslims mostly back the overwhelmingly Sunni rebels in Syria, while many Shiites support Assad, who is a member of Syria's minority Alawite sect, an offshoot of Shiite Islam.