TRIPOLI, Lebanon Lebanese supporters of rival factions in Syria's civil war battled overnight in the city of Tripoli in the worst such bout of spillover violence since the conflict started two years ago.
One person was killed and many were wounded as Sunni and Shi'ite Muslim gunmen fired mortar bombs and rocket-propelled grenades at each other in a fifth day of clashes in the coastal city, security sources said on Wednesday.
Syrian activists said the fighting in Tripoli was triggered by an assault on the Syrian border town of Qusair, where fighters from Lebanon's Shi'ite Hezbollah movement are helping Syrian government forces.
At least 13 people have been killed and more than 120 wounded in Tripoli since it started, the security sources said.
Tripoli has suffered sporadic sectarian violence since the Suuni-led uprising against President Bashar al-Assad broke out in February 2012, but residents said this was the fiercest so far.
Its Sunni Muslims are sympathetic to the rebels but members of the Alawite minority sect, the same offshoot of Shi'ite Islam to which Assad belongs, largely support the Damascus government.
The Lebanese army deployed troops to patrol the two neighbourhoods where fighting erupted and the city was relatively quiet during Wednesday daytime, except for occasional sniper fire, residents said.
In the overnight clashes, grenades and mortar bombs shook the city, even crashing into neighbourhoods far away from the centre of the fighting.
Local politicians said that efforts to meet and discuss a ceasefire agreement have so far failed. Each side accuses the other of using Tripoli as a base for sending fighters and weapons in and out of Syria.
Footage of funerals for Hezbollah fighters killed in Qusair was being watched Shi'ite areas across the country, raising sectarian tensions in other parts of Lebanon, which suffered its own civil war from 1975 to 1990.
In the southern coastal city of Sidon, followers of a Sunni cleric blocked a funeral procession for a Hezbollah militant.
Lebanese soldiers tried to break the blockade, leading to an exchange of gunfire between the Islamist protesters and security forces, residents said. No injuries were reported.
(Reporting by Nazih Saddiq; Writing by Erika Solomon; Editing by Angus MacSwan)