Lebanese army soldiers on Sunday shot dead a Sunni Muslim cleric who backed the uprising against Syrian President Bashar al-Assad, local media reported.
The military said in a statement that it was investigating the incident near an army checkpoint near the northern city of Tripoli, where Sunni Muslims last week fought deadly clashes with Alawite supporters of al-Assad, dpa reported.
Ahmed Abdel Wahed, known for his backing of the popular uprising against al-Assad, and an aide were killed of gunfire wounds after soldiers fired on them in the of Koueikhat, his supporters said.
The army regretted the incident in a statement and said it was investigating. It gave no further details.
The violence in Tripoli between supporters and opponents of the Syrian regime has raised fears that the conflict in Syria will spill over to Lebanon.
Angry protesters blocked used burning tyres to block roads in northern towns after word spread that the cleric had died.
At least 10 people were killed in clashes between residents of Tripoli's mainly Alawite neighbourhood of Jabal Mohsen and Sunni rivals in the district of Bab al-Tabbaneh. Al-Assad is a member of the Alawite sect, an offshoot of Shia Islam.
The Syrian crisis has divided Lebanon between the Western and Arab-backed opposition and the powerful Shiite movement Hezbollah, which dominates the Lebanese government and is allied with Syria and Iran.