Rebels say foreigners have joined them, including some who claim allegiance to al-Qaeda.
Clashes have erupted for a fourth day in Lebanon’s northern city of Tripoli, breaching a truce agreed by local political leaders less than 24 hours earlier in a bid to halt fighting prompted by tensions in neighbouring Syria.
The sectarian clashes began on Thursday after armed men in a nearby Sunni area shot dead an Alawite man. Nine others were wounded in the subsequent fighting.
At least 13 people have died and more than a hundred have been wounded in fighting this week between rival pro- and anti-Damascus fighters, reflecting sectarian faultlines that have emerged in Syria’s conflict.
Syria’s majority Sunni Muslim population has been the backbone of the revolt against President Bashar al-Assad, whose minority Alawite sect has mostly stood with him.
Sunni-Alawite tensions have not only been growing in Syria but in parts of Lebanon as well, like Tripoli, where the two groups live in neighbouring districts.
The army deployed troops and tanks on the streets on Thursday morning to calm the streets and clashes appeared to die down in most areas, residents said.
Residents say political leaders in the city agreed a ceasefire on Wednesday but that when direct clashes, sniping by both sides has continued.
Ten Lebanese soldiers have been wounded in efforts to stop the violence in Tripoli this week. A previous round of fighting in June killed 15 people.
The violence in Tripoli, Lebanon’s second largest city, has seen machine guns and anti-tank rockets being fired.
Najib Mikati, the Lebanese prime minister who is a native of Tripoli himself, raised fresh concern on Wednesday over “efforts to drag Lebanon more and more into the conflict in Syria when what is required is for leaders to co-operate … to protect Lebanon from the danger”.
The authorities have instructed the army and security forces “to bring the situation under control, to prohibit any armed presence and to arrest those implicated” in the violence, he said in a statement.
Later an army statement said: “Due to the gravity of the situation and in order to prevent attempts of dragging the whole of Lebanon into a state of unrest… the army command announces it will enter into dialogue with the city’s leaders and officials, particularly in Bab al-Tebbaneh and Jabal Mohsen.”
France and United States have expressed concern over the latest flare-up and warned against a spillover of the Syrian conflict.
The latest unrest in Tripoli, which has been the scene of several deadly incidents over the past year, follows a wave of tit-for-tat kidnappings of Lebanese citizens in Syria and of Syrians living in Lebanon.
Last week, an armed Lebanese Shia clan claimed it had kidnapped around 20 Syrians in retaliation for the abduction of a family member by a Syrian rebel group, which accused him of being a sniper with the Shia movement Hezbollah.
Hezbollah, considered Lebanon’s most powerful military force, has denied any connection with the clan member or the kidnappings.
Meanwhile, the opposition Syrian National Council has accused authorities of failing to act over the attacks and implicitly blamed Hezbollah which heads a ruling coalition in Lebanon.