Three members of the Lebanese security forces were also injured in the clash, which began after Lebanese forces raided a house in the Wadi Khaled area, where the group that was suspected of planning attacks was holed up, the sources said.
The group included Syrians and Lebanese, the sources said, adding that the scale of the clash, in which militants fired rocket propelled grenades, prompted the Lebanese army to cordon off the area.
The sources said the group included people linked to the militant Khaled al-Talawi, who was killed earlier this month in a shootout with security forces. Four Lebanese soldiers were killed in that clash.
Talawi was described as a former member of the Islamic State group and leader of a cell behind the killing in August of three people in north Lebanon.Maariv contributed to this article.