The Lebanese Armed Forces have been deployed heavily in the north of the country to prevent potential conflict and after thousands of fleeing Syrian Alawites crossed the border, reigniting tension, security sources told The National on Wednesday.

More than 10,000 members of the Alawite minority, fleeing sectarian violence in Syria, have crossed into Lebanon in recent days and settled in northern areas. The situation has heightened tension and raised fears of past conflicts.

Lebanon now fears sectarian violence from Syria’s coast could once again spill over into its volatile north, particularly in the adjacent Bab Al Tebbaneh and Jabal Mohsen districts of Tripoli, where Sunni and Alawite gunmen have engaged in deadly clashes several times over the past 15 years.

About 1,380 civilians, the vast majority of them Alawites, were killed in a wave of violence that gripped Syria's Mediterranean coast, according to the UK-based Syrian Observatory for Human Rights, a war monitor. Since the rebels took control in December, there have been violent campaigns on Syria's west coast, with reports of killings targeting members of the minority group, as well as casualties among security forces. The latest attack began last week after two members of pro-government forces were killed in an ambush.

“Lebanese security forces are heavily deployed in Tripoli and surrounding areas,” one security source said, where they are "heavily focused on preventing conflict". He added: “There is growing fear that the situation could spiral out of control but security forces have so far managed to maintain calm and prevent any alarming clashes.”

Tripoli is home to 200,000 people, 80 percent of whom are Sunni Muslims, 6 to 7 percent Alawites, and the rest Christians. Residents of Bab Al Tebbaneh supported the uprising against former Syrian president Bashar Al Assad, while those in Jabal Mohsen backed him. The two factions have frequently clashed since the Syrian civil war erupted in March 2011.

Small radical Sunni groups in Lebanon have also sent fighters across the border to join the rebels.

The collapse of Syria's army in December has flooded the region with firearms, allowing Lebanese gun dealers to profit by buying cheap weapons and smuggling them into Lebanon. According to security sources, the price of an AK-47, for example, was about $25. Thousands of weapons have been smuggled through illegal border crossings, particularly in the north.

As the rebels appeared poised to take control of Damascus, Lebanon immediately closed all its land border crossings with Syria, except for the main one linking Beirut to the Syrian capital. However, many illegal border crossings, especially in the north, have remained open.

Lebanon has long struggled with the widespread presence of firearms and weaponry. The ruling establishment, which has governed since the civil war (1975–1990), remains heavily armed. Current and former officials from the Tripoli area are set to meet on Friday to discuss ways to ease tension and prevent further conflict, the sources said.