Lebanon's army soldiers hold their guns while securing an area, where clashes between the army and Sunni Muslim gunmen took place, in Beirut on Oct. 22, 2012 REUTERS

Soldiers in armored vehicles were deployed in Lebanese capital Beirut and northern city of Tripoli Tuesday as domestic tensions flared over the killing of top Lebanese security official Maj. Gen. Wissam al-Hassan in a car bomb explosion in Beirut Friday.

At least seven people were killed and dozens wounded in sectarian clashes between the factions supporting and against the Syrian regime in Beirut and Tripoli Monday, heightening fears of a spillover of the Syrian civil war into the neighboring nations.

U.S. State Department Deputy Spokesperson Mark C. Toner Monday expressed concern over the situation in Lebanon saying Washington had been warning about the possibility of a spillover effect from the conflict in Syria.

“There is going to be an FBI team headed to Lebanon to help with them with their investigation, but we’ll certainly wait for the results" of the investigation before offering assistance, Toner said during a press briefing.

However, he stopped short of calling the present crisis in Lebanon a spillover, saying the Obama administration will wait for the outcome of the FBI investigation.

When asked about the reports that the U.S., France and Britain had encouraged Lebanese Prime Minister Najib Mikati to stay in charge, Toner said U.S. Secretary of State Hillary Clinton in a phone call to Mikati Sunday stressed on Washington’s support for Lebanon’s sovereignty.

Lebanese opposition have called for the government, dominated by Hezbollah — Syria’s chief Lebanese ally — to step down, following the bombing that killed al-Hassan, a close friend of anti-Syrian leader Saad al-Hariri.

In a meeting Monday with Lebanon’s President Michel Sleiman, a senior U.N. official and representatives of the five permanent members of the U.N. Security Council expressed their support for the Lebanese government.

“In their statement, Council members underlined their determination that the perpetrators and sponsors of this terrorist act should be brought to justice, and their unequivocal condemnation of any attempt to destabilize Lebanon through political assassination and expressed their determination to support the Government of Lebanon to put an end once and for all to impunity in Lebanon,” a news statement issued by the U.N. Special Coordinator for Lebanon, Derek Plumbly, said.

U.N. Secretary-General Ban Ki-moon spoke with Mikati and Sleiman over the weekend to express his outrage over Friday’s bombing and expressed solidarity with the country's people. “He also commended how the matter how been dealt with by its leadership,” a U.N. statement said.