Brigadier General Jamil Zeidan died in hospital after unidentified assailants shot him in Ain El-Hilweh, the largest Palestinian refugee camp in Lebanon, the National News Agency reported.
A senior Fatah official confirmed Zeidan's death to Reuters.
Shootings and armed clashes are not uncommon in the camp, which houses about 50,000 refugees. Fighters supporting the mainstream Fatah party often clash with militant Islamists.Hostilities in the camp have increased as regional tensions rise, with violence spilling over from the civil war in neighboring Syria.