U.S. Ambassador to West Germany Richard Burt said today, "There is very clear evidence that there is Libyan involvement" in the discotheque bombing here Saturday that left an American soldier dead and 64 other Americans among the injured.

"I don't think there's any disagreement . . . in Berlin or, for that matter, in the conversations I had with senior West German officials over the weekend, that there were clear indications the Libyans were involved," Burt said in Bonn in an interview on NBC-TV's "Today" show.

An American official here, elaborating on Burt's comments, claimed that investigators have gathered "hard evidence" that agents of Libyan leader Col. Muammar Qaddafi were responsible for the bombing and said the Libyans operated through the People's Bureau, or embassy, in East Berlin, the East German capital.

The official provided no further details, however, on what he meant by "hard evidence" and it remained unclear whether the evidence showed direct Libyan involvement in the bombing or the use of German or other foreign agents.

U.S. authorities have anticipated Libyan terrorist strikes since fighting erupted between the two countries in the Gulf of Sidra on March 24 and 25.

On "Today," Burt said the United States told the Soviets and East Germans last week that "we were concerned about the possibility of an attack coming from the Libyan Peoples' Bureau."

The West German government today distanced itself from assertions of Libyan involvement in the incident, although it left open the possibility that foreigners played a role. One West German official, voicing caution, said that the link between Libya and the bombing is "not completely clear."

The ongoing investigation has not firmly traced the bomb to West German or foreign terrorists, a West German Interior Ministry spokesman said in a Bonn press conference today. Spokesman Hans-Guenter Kowalski said, however, that the bombing followed a pattern of earlier attacks against Americans in other countries. He added that there was no evidence that West German left-wing urban guerrillas might have been involved.

"We have strong suspicions, but no proof" that Libyans planted the bomb, a Foreign Ministry official said in a telephone interview.

A West German police task force, which includes U.S. military authorities, is investigating the bombing, but there are reports that U.S. security officials are conducting a separate investigation.

If Libya's involvement can be documented, "We are fully prepared to take the proper countermeasures," the Foreign Ministry official added. "We remain in close contact with the Americans."

On Sunday, following consultations between Burt and senior West German authorities, Foreign Minister Hans-Dietrich Genscher formed a commission to investigate the possibility of foreign government involvement in the bomb attack. In a statement issued in Bonn, Genscher said that proper actions would be taken if the commission's findings are positive.

The West German government already has responded to the recent rise in terrorist activity in Europe by stepping up surveillance of the Libyan mission in Bonn, heavily scrutinizing incoming Libyans and other Arabs at the borders, and upgrading protection of U.S. facilities across the country. But unlike France, Bonn so far has not expelled any Libyan diplomats.

The Reagan administration called on Western European governments last Saturday to oust Libyan representatives to help control terrorist actions.

Effective control of terrorism in West Berlin would require cooperation of the East Berlin and Soviet governments, diplomats here said.

"The border [from East to West] is not very well policed," one western diplomat suggested. Diplomats commuting from East Berlin are routinely whisked across the border without even perfunctory checks of the cars, the diplomat said.

Libya, a Soviet ally, maintains one of its largest foreign missions in the East German capital, with more than 30 diplomats, according to sources here.

Libya does not have official representation in West Berlin, which remains under French, British and U.S. authority, according to post-World War II agreements.

West Berlin, in addition to a Turkish population of 150,000, has enclaves of various groups from the Middle East, including thousands of Palestinians, Iranians and Iraqis. Many have flown into East Berlin and crossed the border into the West, where they have requested political asylum.

Senior East German official Gunter Mittag and West German officials in Bonn are expected to discuss the policing of the border between East and West Berlin, among other issues, when they meet in the West German capital this week, West German sources said.

Of the 64 Americans injured in the bombing of the disco, La Belle, 30 were still hospitalized in Berlin or the Army hospital in Landstuhl, West Germany. Two GIs and two U.S. civilians remain in serious condition, according to military sources. Apart from the American soldier, a Turkish woman was also killed in the explosion.

Over the weekend, many patrons who had left the bombed disco in a daze reported back to local hospitals, bringing the total injured to 204.

Maj. Gen. John Mitchell, U.S. commander in Berlin, assailed international terrorism during a visit to injured soldiers in the U.S. military hospital here today.

Describing terrorism as "a crime, a senseless, immoral act" against defenseless people, he called on the GIs to assist in "stamping it out just as you would if you were facing the enemy with a rifle in your hands.