Two explosions have rocked the mosque of al-Takqa and al-Salam in the northern Lebanese city of Tripoli killing at least 12 people who were there for Friday prayers.

The first blast reverberated through the city centre outside the al-Taqwa mosque near the home of outgoing prime minister Najib Mikati. A spokesman for his office said that he was not in Tripoli at the time.

The mosque is where hardline salafist preacher Sheikh Salem Rafie makes his sermons railing against the regime of President Bashar al-Assad in Syria.

The second bomb was detonated near the port of the Sunni-majority city. Thick black smoke billowed as gunshots were fired into the air.

The National News Agency said another 25 were wounded in the blasts.

Tripoli has previously seen clashes between Sunnis and Alawites, a Shiite offshoot sect to which Assad belongs.