Clashes broke out in a Palestinian refugee camp near the southern Lebanese port of Sidon on Monday, killing seven people, including the commander of an armed group, and wounding at least 10 others, Lebanese and Palestinian security officials said.
It was not clear what triggered the fighting in the Mieh Mieh camp, which pitted supporters of a former commander of the mainstream Palestinian group Fatah and members of a rival armed group, Ansarullah.
Officials said heavy machine guns and rocket-propelled grenades were used in the fighting. They spoke on condition of anonymity in line with regulations.
Fighting is common between rival groups across Lebanon's twelve Palestinian refugee camps, which house about 450,000 refugees and their descendants who were displaced by war since the 1948 creation of the state of Israel.
The nearby Ein el-Hilweh camp, Lebanon's largest, is the scene of frequent bombings, assassinations and shootings among rival factions vying for control of the camp.
The army blocked all roads leading to the Mieh Mieh camp later Monday to contain the fighting, which raged for almost two hours. Ambulances raced outside the camp, ferrying the wounded.
Among those killed were Ahmad Rashid, commander of the Al-Awda Brigades, which are affiliated with Fatah, as well as his brother, Rashid, and his bodyguard.
In other developments, the chief of the Shiite Lebanese group Hezbollah on Monday claimed responsibility for a March 14 roadside bombing that targeted an Israeli patrol along the Lebanon-Israel border.
Hassan Nasrallah told Lebanese daily A-Safir that the bomb was in response to a February air strike on a Hezbollah base that the group blames on Israel.
Nasrallah said the March bombing sent a message that Hezbollah was still capable of fighting Israel, even as its fighters are battling alongside Syrian President Bashar Assad's forces to quell a three-year uprising.
No Israeli soldiers were hurt in the March bombing. Such attacks have been rare since the 2006 Israel-Hezbollah war, and both sides have avoided direct confrontation.