A radical Lebanese cleric and his followers have been using their mosque complex as a weapons arsenal, according to the Middle East news site Al Arabiya.

The mosque complex was a focal point of deadly clashes in Sidon on Sunday and Monday which appears to be the latest evidence of the Syria conflict spreading into neighboring Lebanon.

The Lebanese military found large amounts of weapons and ammunition including rocket launchers, machine guns, and fatigues stashed away in the place intended for prayer.

Massive Weapons Arsenal Found in Mosque at Center of Deadly Lebanon Clashes

Weapons were found in the Sidon mosque complex (Screenshot from Al Arabiya)

Reporters on the scene said the complex includes a mosque and office buildings and is situated in a residential area.

Al Arabiya reports that 17 soldiers and 50 loyalists to radical Sunni cleric Ahmed al-Assir were killed in the southern Lebanese city of Sidon. The Lebanese army took control of the Bilal bin Rabah mosque, but Assir escaped and his whereabouts are unknown.

Now, there is a “massive manhunt” underway for the cleric.

AFP reports from Sidon:

The violence began on Sunday evening, when Assir’s supporters opened fire on an army checkpoint, reportedly after a car carrying his backers was stopped.

The clashes quickly spread, with his supporters and the army exchanging gun and mortar fire, terrifying local residents.[…]

The complex in Abra, on the eastern outskirts of Sidon, is a residential area and dozens of civilians were trapped by the fighting, which left several apartments in the area burned out.

Reuters reports, “Late on Monday, clouds of smoke rose from the mosque. Assir’s office across the road was completely destroyed. At least four tanks and several army vehicles at the scene had been torched. Assir remained at large.”

Massive Weapons Arsenal Found in Mosque at Center of Deadly Lebanon Clashes

A smoldering building at the scene of the fighting between the Lebanese military and Sunni radicals in Sidon (Screenshot from Al Arabiya)

Soldiers stepped in to free civilians who were trapped in their homes during the two days of fighting. They also detonated explosives left by the cleric’s supporters.

The fighting is being described as the worst Lebanon has seen since the Syria conflict began next door.

Assir is known for his opposition to the Shiite radical group Hezbollah – which has sent fighters to bolster President Bashar Assad’s forces in Syria. Assir has encouraged his followers to travel to Syria to fight alongside rebel forces. According to Al Arabiya, last week Assir called on his supporters to fire on apartments in Abra that he believes were housing Hezbollah members monitoring his activity.

Also on Monday, violence was reported in Tripoli, Lebanon. Reuters reports that gunmen opened fire on the Lebanese military and “blocked roads with cement blocks and burning tires,” while in the capital Beirut, militias from both sides blocked roads.

The U.S. has condemned the violence, while UN Secretary General Ban Ki-moon criticized the attacks on the Lebanese military.

Israel has also had experience discovering weapons caches in mosques. The Israel Defense Forces has in the past reported that its planes had struck mosques that were being used as ammunition depots.

For example in a 2009 video that can be seen here, a secondary explosion could be seen after Israel Air Force jets struck a mosque. The IDF said the secondary explosion was evidence of “the deliberate use of a place of worship as a military facility. Hamas uses the Palestinian people as human shields and exploits religion in its brutal campaign against innocent civilians.”