UNITED NATIONS, May 21 (Xinhua) -- UN Secretary-General Ban Ki-moon on Monday called on all sides in Lebanon to protect civilians.

    In a statement released by his spokesperson, Ban said he is gravely concerned about the fighting in the last two days between Fatah el-Islam gunmen and the Lebanese army.

    "The actions of Fatah al-Islam are an attack on Lebanon's stability and sovereignty," the UN chief said.

    He welcomed the "united stand taken by Palestinian factions in Lebanon denouncing these attacks on the Lebanese army" and called on all sides to do their utmost to protect innocent civilians.

    Ban also strongly condemned Sunday's terrorist bombing in Beirut, and urged the Lebanese "to unite in the face of threats to their stability and security."