At least six people have been killed in renewed fighting in the Lebanese city of Tripoli, between supporters and opponents of the Assad regime in neighboring Syria.

Lebanon’s second city has long been riven by sectarian strife, but has seen tensions strained beyond breaking point since the onset of the Syrian civil war. Regular gun battles pit Sunni militias in the Bab al-Tabaneh neighborhood – who support the mainly Sunni Syrian rebels – against Alawite fighters in the Jabal Mohsen district who support the Alawite-led Syrian government.

At least four of the dead were from the Sunni-majority Bab al-Tabaneh, and at least 30 people were injured in the clashes.

According to Reuters news agency, at least five of the wounded are soldiers from the Lebanese national army, which has been struggling to keep the warring factions apart, and which is often caught in the crossfire as a result.

Many of the dead and wounded were hit by sniper fire from the uphill neighborhood of Jabal Mohsen, in what residents say is a response to a recent spate of attacks on local Alawites.

Relations between Lebanon’s delicate patchwork of religious communities has been put under immense strain due to ongoing fighting in Syria. Lebanese nationals have been flowing across the border to suppor their coreligionists on both sides of the civil war there, but hostilities have spilled over into Lebanon itself on a number of occasions.

Back in August two car bombs killed 42 people outside Sunni mosques in Tripoli. That attack came after two separate car bombings left more than 20 dead and scores injured in attacks on Shia-majority areas of Beirut, a stronghold of the Hezbollah terrorist group which has been fighting alongside Syrian regime forces against the rebels.

Earlier this month, a double suicide-bombing killed 25 people in an attack by Sunni Islamists on the Iranian embassy in Beirut.