July 18, 1981

The Reagan Administration today postponed a planned announcement that the United States was resuming delivery of F-16 fighter-bombers to Israel. At the same time, without directly criticizing Israel, the Adminstration called for a cease-fire in the warfare across the Israeli-Lebanese border. The Administration's actions followed air strikes early today by Israeli jets against what Israel said were Palestine Liberation Organization facilities in Beirut and targets in southern Lebanon. The air action in Lebanon was the most severe since Israeli troops moved into the southern part of the country in 1978 and was the fifth Israeli raid in a week against Palestinian targets in Lebanon.

Two crowded ''sky bridges'' inside the lobby of the Hyatt Regency Hotel here collapsed tonight, killing at least 45 people and injuring about 145, according to the police and rescue workers. Four and a half hours after the disaster, with the ruins of the walkways remaining to be lifted from the floor, the authorities said the toll could go much higher once the debris was removed with heavy equipment sent to the scene. ''We have found six people still alive who are trapped between the two skywalks,'' said Sgt. Jim Treece, a spokesman for the Police Department. ''We still don't know how many people are trapped, but there were 1,500 people in the lobby when it happened, and God only knows how many are still in there.''

Wayne B. Williams, a 23-year-old music promoter and talent scout, was indicted today on charges of murdering two of the 28 young black people slain here in the last two years. A Fulton County grand jury charged Mr. Williams with murdering Nathaniel Cater, 27, ''by strangling and asphyxiating'' him. The Cater slaying, the last one to occur, is the case in which Mr. Williams was arrested last month. The grand jury also charged Mr. Williams with murdering 21-year-old Jimmy Ray Payne ''by asphyxiating him with objects and by means which are to the grand jury unknown.''

Voting for the first time by secret ballot, delegates to the emergency congress of the Polish Communist Party elected a new Central Committee today, sending some of the most prominent figures in the leadership down to defeat. Leaders of both liberal and conservative extremes among the 279 condidates were eliminated in the single-ballot vote for the 200 seats on the committee. The centrist position of Stanislaw Kania, the centrist position of Stanislaw triumphant, a strong indication that Mr. Kania will be re-elected as First Secretary by the entire congress. Challenger to Kania Loses Tadeusz Grabski, a conservative on the Politburo who had undertaken a challenge against Mr. Kania and was planning to oppose him for the party leadership, lost getting 899 votes.

As Israeli planes struck at Beirut today, further widening the war against Palestinian guerrillas, Prime Minister Menachem Begin announced that the guerrillas could no longer expect to hide amid civilian populations in Lebanon. The warning, contained in a statement issued from the Prime Minister's office, was intended to press Lebanese authorities to curb Palestinian military operations against Israel from Lebanese soil. The Israeli planes struck at what officials said were two Palestinian headquarters buildings in the center of Beirut. An Israeli military spokesman said offices of two organizations - Al Fatah and the Democratic Front for the Liberation of Palestine - were destroyed, but he said nothing of casualties. Reports from Lebanon described civilian casualties as heavy.