A sniper shot dead one person on Wednesday in the northern Lebanese city of Tripoli, and four others were wounded in an exchange of gunfire that followed, a security source said.
The violence erupted between pro- and anti-Syrian neighbourhoods of the city that have seen deadly clashes in the past few months, but it was not immediately clear if the latest flare-up was directly linked to the Syria conflict.
The security source identified the dead man as Talal Azaya, a resident of Bab Mohsen neighbourhood, and said he was killed by a sniper posted in the adjacent district of Bab el-Tebbaneh.
Four people were wounded in an exchange of fire that followed the shooting, the source said.
An AFP correspondent in the city said the violence erupted in the mid-afternoon after a grenade was lobbed into Jabal Mohsen, wounding a young man.
As his relatives rushed him to hospital gunmen opened fire on them, wounding two people, the correspondent said.
The army issued a statement in the evening saying the man wounded in the grenade attack was a soldier.
The military said it arrested several people and set up roadblocks in the area, while soldiers were sent to patrol the streets.
Tripoli has been rocked by deadly clashes between supporters and opponents of the Damascus regime, where a two-year conflict has killed at least 70,000 people according to UN estimates.