The Central Intelligence Agency says it was not involved in a Beirut car bombing that killed 80 people in March, and has criticized a Washington Post article last month on the incident.

The Post's May 12 article said that President Reagan directed the CIA late last year to train and support counterterrorist units, made up of Lebanese and other foreigners, for strikes against suspected terrorists before they could attack U.S. targets.

The story said that in March, members of one of those units, "acting without CIA authorization, went out on a runaway mission and hired others in Lebanon" to plant a car bomb outside the residence of a militant Shiite leader believed by intelligence sources to be behind terrorist attacks on U.S. installations.

The story said "CIA personnel had no contact with those who actually carried out" the bombing. But it added that "faced with an indirect connection to the car bombing," U.S. officials canceled the support operation.

The CIA, in a letter to The Post by spokesman George V. Lauder, published in the letters column today, said the story "gave the American public and the rest of the world the totally false impression that the U.S. government was involved in terrorist activity.

"This misleading theme has been picked up by a number of other journalists as fact and has even been cited by the Shiite terrorists as one of the motives for hijacking TWA Flight 847."

The letter comes as administration officials are concerned that some hostages from the hijacked plane are reportedly in the hands of the group headed by the target of the March 8 bombing, Mohammed Hussein Fadlallah, leader of the Hezbollah (Party of God) militant Shiite faction.

Fadlallah, who was unharmed, has been tied in U.S. intelligence reports to the bombings of the Marine headquarters that killed 241 in 1983 and the bombing of the U.S. Embassy annex last fall.

The CIA letter to The Post added that a House intelligence committee review of the incident concluded on June 12 that there was no CIA complicity in the bombing.

Two members of the committee said yesterday that the report did not directly address The Post article.

The report, they said, dealt with a resolution by House members who accused the CIA of financing hit teams because of the bombing. That resolution demanded CIA documents about the bombing.

Senior CIA and administration officials, before and after The Post article was published, confirmed the details.

One senior CIA official said the article was accurate, but he had a problem with "the way it got picked up . . . as if we had our own hit team out there."

CIA Director William J. Casey said in an interview in U.S. News & World Report last week that the Lebanese had asked the CIA "to help plan preemptive action. Before the bombing we were ready to consider helping them with planning of that sort of action if they did it in a surgical, careful, well-targeted way -- if they really knew what they were doing."

He said that the CIA had given the Lebanese training and technical support to deal with terrorism. "But they do any operations themselves," Casey said. "We were not involved, and no one we trained was involved in the Lebanese car-bombing operation."

Asked in the U.S. News interview if the March 8 bombing led to a change of policy, as The Post and other news organizations reported, Casey said, "Well, we didn't like the way that situation was handled. So we pulled back from any involvement in the planning or preparation of operations."

CIA spokesman Lauder could not be reached for comment yesterday. CIA spokesman Patti Volz said the letter was not written until Friday, nearly six weeks after the story, because the CIA just learned about the House committee report. She said she "wouldn't address" questions on whether the letter was part of any administration effort to send a message to the TWA hijackers.

Several other publications, including The New York Times, The Wall Street Journal, Newsweek and the Los Angeles Times, and CBS News later carried similar stories of the birth and cancellation of the administration's counterterrorism program in Beirut.

In his letter, Lauder said the CIA categorically denied any involvement with the bombing both before and after the article was published, and The Post ignored the denials. The Post article said administration spokesmen had no comment before publication.

The Post carried the public CIA denial in the middle of an article about congressional inquiries into the matter.

Lauder also quoted from the House report that said its review "leads to the conclusion that no U.S. government complicity, direct or indirect, can be established with respect to the March 8 bombing in Beirut."

The House report is a public document, but was not printed in the Congressional Record or distributed to reporters, a committee staff member said. It said the committee review uncovered no evidence that government agencies "encouraged or participated in any terrorist activity in Lebanon."

It also said the committee discovered no evidence that U.S. intelligence had foreknowledge of the bombing.

The Post article was headlined: "Antiterrorist Plan Rescinded After Unauthorized Bombing." It did not say the CIA knew about or encouraged the bombing.

In the U.S. News interview, Casey also said he did not believe planning an operation that was likely to kill people amounted to assassination, which is illegal under U.S. law.

"If the Lebanese discharge their duty to protect the lives and property of their citizens as well as other nationals, and if in the course of doing that someone gets killed, are we assassinating that guy? No. We're helping the Lebanese perform a security function.

"If someone gets killed or hurt, well, it's a rough game. If you don't resist and take protective action against terrorists because you worry that there's going to be somebody who might say, 'Ah, that's assassination,' then terrorists can own the world, because nobody's going to do anything against them."