TRIPOLI, Lebanon (AFP) - A man preparing a bomb was killed on Saturday when it went off prematurely in Lebanon's restive northern city of Tripoli where another person was also shot dead, a security source said.

Another two people were wounded when the device exploded in Baqar, a neighbourhood in western Tripoli, the source said, identifying the dead man as a Sunni Muslim Islamist.

After the blast, gun battles broke out between Baqar, a Sunni Muslim neighbourhood, and Jabal Mohsen, an Alawite district. Four Sunnis were wounded, one of whom later died.

The army later intervened to restore calm.

Violence has regularly broken out in Tripoli, a majority Sunni city, between residents and the minority Alawites - an offshoot of Shiite Islam - in Jabal Mohsen.

The clashes have become more frequent and deadly since the beginning of the Syrian uprising in March 2011, which pits the Sunni-led opposition against the regime of President Bashar al-Assad, an Alawite.