A sniper shot dead a soldier as sectarian clashes rocked northern Lebanon, the country's national news agency has said.
NNA said the soldier was shot and killed while he was inside a car in the city of Tripoli.
NNA later said two civilians had also been killed in the violence.
The clashes highlight how easily unrest in neighbouring Syria can raise tensions in Lebanon.
Residents say gunfire broke out in the city yesterday and continued through the night, primarily between a neighbourhood populated by Sunni Muslims who hate Syrian president Bashar Assad and another area with many Assad backers from his Alawite sect.
Armed civilians patrolled the streets today, and the Lebanese army said it was sending troops to control the area.
Similar clashes in the area in February killed two people.
A man was found dead on the side of a road while a second died after a shell landed in a residential neighbourhood, both in Tripoli.
A witness in the city said the Lebanese army had sent reinforcements, but gunmen still patrolled the streets and intermittently shot at each other with automatic rifles. Heavier weapons, like rocket-propelled grenades, have also been fired.