The Lebanese army has been deployed in Tripoli to try prevent further clashes between gunmen from opposition and pro-government groups.
Lebanon has entered a new phase of uncertainty without a president
Fighting broke out on Tuesday between a newly-formed group loyal to parliamentary majority leader Saad Hariri and a local Islamist group.
A member of the pro-Syrian Islamic Unification Movement (IUM) died during the fighting, police said.
It comes amid a sharp political crisis and fears of a return to civil strife.
IUM and Tripoli Brigades members exchanged automatic fire in the Abi Samra neighbourhood in the northern port city.
In all seven people were wounded during the clash. Reports say a second man, from the pro-government Tripoli Brigades, died of his injuries later in hospital, but this has not been confirmed.
Security sources are quoted saying the bloodshed occurred near the IUM's headquarters and was sparked by a dispute between two men.
Police said the army deployed in the area and calm was restored on Tuesday evening.
Lebanon has been without a president since last week, when Emile Lahoud left office without any elected successor.
The rival pro-Western government and their pro-Syrian counterparts remain deadlocked over filling the position.
They have pledged to agree a candidate by Friday when MPs convene again to hold the vote that has already been postponed a number of times. It is Lebanon's worst internal political crisis since the country's long civil war ended in 1990.