Gunmen armed with rifles and rocket-propelled grenades have exchanged fire in southern districts of Lebanon's capital Beirut, security sources said, and residents could also hear the sound of ambulance sirens.

There were no immediate reports of casualties from the clashes on Sunday night, which occurred after angry mourners tried to storm government offices in the center of Beirut at the end of the funeral of an intelligence official assassinated on Friday.

Violence erupted after protesters tried to storm the offices of Najib Mikati, the prime minister, following the funeral of an assassinated intelligence chief whose death they blame on Syria.

Security forces shot into the air and police fired tear gas on Sunday to repulse the hundreds of protesters who overturned barriers and threw stones and steel rods, witnesses said.

The funeral of General Wissam al-Hassan had been billed as a protest against Syrian meddling in Lebanon, but quickly turned into equal, if not greater, anger at Mikati and his government.

An angry crowd had marched on the government's headquarters, or the Serail, after politicians at the funeral of Brigadier-General Wissam al-Hassan, who was killed by a car bomb on Friday, called on him to resign over the killing.

Al Jazeera's Gregg Carlstrom, reporting from the scene of the violence, said about 50 opposition supporters tried for up to half an hour to approach the Serail, throwing sticks, rocks and rods until they were dispersed by Internal Security Force (ISF) personnel.

"The whole country will be shut down until Mikati resigns. We are going to block roads, we are going to protest," Ahmad Balaa, a young activist of the opposition March 14 alliance who was among the protesters, told Al Jazeera.

Automatic gunfire

Authorities responded with tear gas and several officers fired machine guns and rifles in the air.

One plainclothes guard pulled a pistol from his belt and fired over protesters' heads. Then a roar of automatic gunfire erupted, sending the protesters scattering for cover.

It was unclear if the guards fired live bullets or blanks, but no protesters were reported injured by gunfire.

Several were overcome by tear gas, and the government's media office said 15 guards were injured.

Unrest also broke out elsewhere in Lebanon. Protesters blocked major roads in Beirut and in the north with rows of burning tires, and briefly closed the country's main highway to the south, the national news agency said.

Clashes erupted in the northern city of Tripoli, with residents of two neighborhoods that support opposite sides in Syria's civil war, exchanging gunfire.

Al Jazeera's Hoda Abdel-Hamid, reporting from Tripoli, said that there were reports of a Sunni Muslim woman getting killed by a sniper.

The latest clashes fed into a growing political crisis in Lebanon linked to the civil war in neighboring Syria.

The opposition and its supporters believe Mikati is too close to Syrian President Bashar al-Assad and his Lebanese ally Hezbollah, which is part of Mikati's government.

PHOTO CAPTION

Lebanese President Michel Suleiman, Prime Minister Najib Mikati, and other government officials pay their last respects on Sunday to the slain Wissam al-Hassan, who was killed in a car bomb last Friday [EPA]

Aljazeera