A suicide bomber killed at least six people Thursday at a Muslim clerics' meeting in the Lebanese town of Arsal on the border with Syria, a security source told AFP.

The source said that the bomber entered the meeting of Syrian clerics and "detonated an explosive belt, leaving five people dead and six wounded until now."

One of the wounded later died.

The head of the local clerics' committee, Sheikh Othman Mansur, was also among the wounded, while the state news agency said his deputy, Omar al-Halabi, was killed.

Arsal is a Sunni Muslim enclave in mainly Shiite eastern Lebanon and hosts many Syrian refugees as well as rebel fighters in the surrounding countryside.

"The explosion definitely targeted this meeting... where usually no less than 15 people are gathered," Arsal resident Abu Ibrahim told AFP by telephone.

"I just went to the hospital, and there were people crying and screaming," he said.

Arsal was the scene of fierce fighting in August 2014 between Lebanese security forces and terrorists of Al-Qaeda's Syria affiliate Al-Nusra Front and the ISIS terrorist group.

As they withdrew from Arsal, the terrorists took dozens of Lebanese police and soldiers hostage and still hold them in the hilly terrain on the town's outskirts.