Military police and forensics in white overalls deployed in the northern Lebanese city of Tripoli on Tuesday after a lone gunman killed four security personnel before blowing himself up in an apartment in a residential building overnight.

The rare shooting, in which the gunman used a motorcycle to move around, opening fire on police and army vehicles, shook the predominantly Sunni Muslim coastal city on the eve of the Eid al-Fitr holiday, which marks the end of the holy month of Ramadan.

Interior Minister Raya El Hassan told reporters the gunman, identified as Abdul-Rahman Mabsout, is a former member of the Islamic State in Iraq and Syria (ISIS) and now a “lone wolf.” She said the situation was under control.

The shooting began late Monday with the gunman firing at a branch of the Lebanese Central Bank, then driving around, shooting at police and later at an army vehicle, killing four.

With police opening fire and using tear gas, he then drove to a residential building, where he shot his way up the stairs and into an empty apartment on the fourth floor and barricaded himself inside.

An hours-long standoff ensued, culminating with security forces storming the apartment. Cornered, the gunman detonated his explosives vest, killing himself instantly.

On Tuesday, there were multiple signs of battle. At least four civilian cars and one police car were heavily damaged, their windshields smashed and pocked by bullet holes.

Military police and forensics removed bullets from the street. Tear gas canisters were still on the ground.

The nine-floor apartment building where Mabsout died was shell pocked and the apartment was partially destroyed.

Detained briefly after return from Syria

The owner of the apartment said he and his family were not in the house when the gunman stormed the building, but his flat was left largely destroyed by the explosion. He said the attacker entered his building after shooting one person in the street.

“Thank God there was nobody in the house, and my door is not made of steel, it is a wooden door so I think he broke the door and he walked in,” Kamal Ferri told The Associated Press.

Mabsout was described as a former member of ISIS who fought with the extremist movement in Syria. He had been detained when he returned to Lebanon in 2016 and was released a year later.

The Lebanese army announced earlier it had increased security around the country because of Eid el-Fitr, when people go out to celebrate.

Tripoli, Lebanon’s second largest city, has in the past seen clashes between rival groups that support or oppose the Syrian government of President Bashar al-Assad. The city is also home to some extremists who had fought against the Lebanese army.

Militants linked to ISIS and al-Qaeda militants have claimed responsibility over th years for attacks in different parts of Lebanon that killed dozens of people. Such attacks have been rare recently.