TRIPOLI (AFP) - Lebanese tanks were out on the streets of Tripoli on Saturday to restore security after nine people were killed in a fresh bout of sectarian fighting in the northern port city. Militants from the rival Sunni Muslim and Alawite communities battled with rocket-propelled grenades and automatic weapons through the night in the latest violence to rock the Mediterranean city. Among the dead were a 10-year-old boy and two women, while another 50 people were injured in the fighting that first erupted early Friday and raged through the night despite a ceasfire that was to have taken effect at 1500 GMT. "The army is working for real calm in the north," an army official told AFP, but added: "Security requires political agreement." Lebanon has been hit by sporadic outbreaks of violence despite a power-sharing deal between rival political factions in May which led to the election of Michel Sleiman as president and the creation of a unity cabinet. The latest unrest comes after the new cabinet hit snags in deliberations aimed at drawing up a policy agenda ahead of a parliamentary vote of confidence which would enable the government to be officially installed. "This is a political conflict between the Lebanese. Rather than go to the constitutional institutions, they are reverting to the use of weapons," the army official said. The army was on high alert, with tanks and armoured vehicles patrolling the streets to keep the peace in the mainly Sunni Bab al-Tebbaneh district and the neighbouring largely Alawite area of Jabal Mohsen, both impoverished areas. Sniper fire could still be heard in areas where the army was not yet deployed, an AFP correspondent said. Shops in the area were closed, streets were deserted and many families who evacuated their homes near the battle zone were taking refuge in schools, the Interior Minister Ziad Barud and the head of the internal security forces Ashraf Rifi headed to Tripoli late Friday to see the situation for themselves and to assess measures to restore calm. Clashes between the two sides have killed a total of 23 people and wounded more than 100 since June. "The army has sent reinforcements to the battle zones to secure the ceasefire and the army command has promised us to firmly respond to any violation of the ceasefire," said Sunni MP Mohammed Abdel Latif Kabbara of the parliamentary ruling majority. Bab al-Tebbaneh is a stronghold of the anti-Syrian parliamentary majority while the inhabitants of Jabal Mohsen are mainly supporters of the Syrian-backed opposition led by the powerful Hezbollah movement. In Friday's violence, a rocket-propelled grenade slammed into an apartment building near a vegetable market, setting it ablaze, while another one hit a mosque in Bab al-Tebbaneh. "Every time a sectarian rift breaks out in the north, it is used for political pressure... weapons are being used as a way of making political gains," said majority MP and former sports minister Ahmed Fatfat. The violence erupted after cabinet ministers decided on Thursday night to postpone talks on the issue of weapons held by Hezbollah, the powerful Shia political opposition movement and militia. It is a key bone of contention in Lebanon's fraught political negotiations.