Gunfire in what Lebansese police called one of the worst outbreaks since the halt of the civil war caused panic in the capital today and left at least one dead and 12 wounded. Accounts differed on whether the combatants were rival Palestinian groups or Syrian peacekeeping troops battling Palestinians.

The Arab peacekeeping force blamed the clashes, with machine guns and rocket grenades, on "rival factions in the Beirut subrubs" and said that its troops had to step in to restore order.

Individual members of the Arab force said, however, that the fighting originated between Palestinians of the hardline Rejection Front and Syrian troops.

Washington Post correspondent Stuart Auerbach, visting the area of a reported imminent phased Syrian withdrawal of troops from southern Lebanon, found Syrians there spread so thinly that any phased pullout seemed impracticable.

Syrian troops interviewed said they had heard nothing about any withdrawal, which was reported by informed sources in Washington.

In other Middle East developments:

Arab League countries meeting in Tunis for a dialogue with representatives of the European Economic Community attacked the EEC for its "fundamentally negative" policy on an Arab-Israeli peace settlement.

Egyptians voted in a nationwide referendum on President Anwar Sadat's security law to crack down on Communists and other "subversives" that he blamed for food riots last month.