Fighting that went on long into the night in Beirut erupted after Lebanese troops shot dead two Sunni political figures at a checkpoint on Sunday.

Lebanon's National News Agency said on Monday at least two people were killed in the fighting.

It said at least 18 more were wounded.

When daylight finally came bewildered residents left their homes to survey the damage.

SOUNDBITE: MOHAMMAD SAAB, RESIDENT, SAYING (Arabic):

"This is a real war. We were sitting at home with our children, then we heard gunfire. We didn't know who was shooting at whom."

Witnesses say the fighting involved two Sunni groups firing machine guns and rocket-propelled grenades at each other.

It's unclear how the violence began.

The men whose deaths preceded the conflict were both members of a political alliance opposed to Syria's president.

The bloodshed in Lebanon has raised fears that the turmoil in Syria could be spilling over the border.

Many Sunni Muslims in the north of Lebanon sympathise with Syria's Sunni-led uprising and accuse the Lebanese army of taking orders from Damascus.

Paul Chapman, Reuters