BEIRUT: At least six people were killed in two days of clashes in a Palestinian refugee camp in Lebanon, where the mainstream faction Fatah fought against rival groups that support Islamists, security sources said.

A Fatah commander was killed on Sunday in an ambush that also injured several of his aides in the crowded, impoverished Ain el-Hilweh camp near the southern Lebanese coastal city of Sidon.

Four of the aides later died of their injuries, a security source said, adding sporadic clashes in the camp intensified later on Sunday.

Clashes began the previous day with a failed assassination attempt on a leader of a group sympathetic to hardline Islamists in which one person was killed. That was followed by gunfire and attacks by armed militants on the headquarters of Fatah.

Shops closed their doors and some people fled the camp, the largest refugee camp in Lebanon, as tensions between the rival groups mounted on Sunday, a witness said. The Lebanese army said a mortar fell inside a military headquarters with one soldier wounded.