If a Libyan "hit squad" entered the United States, the FBI has never confirmed it, Director William H. Webster said yesterday.

Asked if the reports of such a hit squad, suppposedly assigned to assassinate President Reagan or other top U.S. officials, could have been planted to put the government "into a tizzy" and even make it "look somewhat silly," Webster replied: "That's always a possibility."

But the FBI director, interviewed on "This Week With David Brinkley" (ABC, WJLA), said bureau investigators "certainly had enough information and continue to receive enough information to require us to take appropriate investigative steps and we will continue to do that." The publicity over the threats, he added, isn't making the job easy.

"I gather you would have been happier had it never been made public at all?" he was asked.

"Yes, I would," Webster replied.

The story of the Libyan death plot is receding from the headlines now, and the FBI's job may be getting easier. But within the government and on Capitol Hill, there's a trail of bad feelings.

Key among those feelings are suspicions that reports of the plot were publicized purposely by some in the administration, as part of an impromptu anti-Libyan offensive. Some officials and members of Congress feel that the publicity diverted attention from a proven threat, Libya's destabilization of African and Middle East countries friendly to the United States.

Interviews with officials and members of Congress who received privileged briefings turned up a consensus that the White House was justifiably concerned over the intelligence reports of a Libyan-trained hit squad supposedly bound for this country to kill the president or other high officials.

Beyond that, however, there is much disagreement. Some felt the evidence did not justify highly visible security precautions, including anti-sniper teams on the White House roof and decoy limousines spurting through Washington's streets.

"I could never discover just what it was that made them take this threat any more seriously than they would any of the others that must come to the White House every day," said one congressman who was briefed in secret.

One of the most critical voices, however, comes from within the administration, where complaints are heard that the White House countenanced or inspired a high-pressure campaign of leaks that distorted the real Libyan danger in the world.

"We are very chagrined over the hype that was put on this by some inside the government," said one high administration source. "We became the victims of our own ineptitude."

This official, who asked not to be identified, feels the episode could have damaged a long-term effort to enlist the support of European allies in a campaign to curb Libyan leader Muammar Qaddafi's attempted subversion of his neighbors, some of them friends of the United States.

Ironically, a State Department study on the Libyan problem had just been presented to the White House at the time the story of the death plot broke in the nation's press in late November. That policy analysis had paid little attention to the reported hit squad threat, concentrating instead on Qaddafi's threats to neighbors such as the Sudan, Chad, and ultimately Saudi Arabia. It also envisioned some joint action of the United States and its allies to force the Libyan leader to desist.

Instead of those documented threats, the official said, the deluge of news leaks from the White House made it appear to allies that "we would be approaching them only on the basis of our reaction to the death threat."

The official said, however, that he now feels the danger of such a misconception had been minimized by President Reagan's decision to "move the story out of the White House," a reference to the new reluctance of presidential aides to discuss the affair.

The Libyan death-threat story broke into public in late November and early December in a blaze of stories. The administration never publicly disclosed details of the plot, but from a variety of sources came reports of one or two teams equipped with missiles that could shoot down Air Force One or destroy the president's limousine. Photographs of suspected terrorists were given to the press and sent to border patrols.

According to one White House aide, the reports came from several sources and when taken together justified ringing the alarm bells. The major source, he said, was a man, nationality unidentified, who defected to a U.S. mission with a story about the hit squad. He was flown to the United States and given four polygraph tests before his account was deemed truthful.

Briefings to key congressional committees convinced many that the extraordinary alert was justified, although those accounts did not always square with more detailed reports appearing in the press. For example, several published reports quoted government sources as saying the hit squad or squads actually came into the United States. In private, administration witnesses told Congress there was no evidence that any hit-squad members had entered this country. The disparities left some members baffled and irritated.

"I personally felt that the evidence presented was sufficient to justify the Secret Service in taking more than the usual precautions and for the FBI to investigate," said Sen. Patrick J. Leahy (D-Vt.).

"But I felt it was unfortunate that so many in the administration were leaking stuff out so that any night you could hear reputable news people come out with contradictory information.

"There was too much public attention by the administration. It built Qaddafi up all out of proportion. The evidence was solid enough to take precautions, but it should have been done quietly. There were a lot of threats in the Carter administration that were as serious as this one. There was nothing there to justify such public statements."

Leahy also said the news media shared part of the blame. "Some people in the White House were pumping the stories out, but also some in the media got carried away."

Several members of Congress said the administration briefers were less than convincing in describing the significance of the alleged defector who had reportedly described the Libyan terrorist training camp.

One apparent result of the episode was a speed-up in the administration's design for removing Americans from Libya, a step that would make more drastic steps against that country easier to take in the future. On Dec. 10, the government called for the return of some 1,500 Americans living in Libya and announced a ban on American travel to that country.

Such measures had long been contemplated in both the Carter and Reagan administrations and may well have been carried out as a result of the State Department analysis begun in September, regardless of any assassination plot. But according to administration sources, the death threat episode played a role in enabling the government to move earlier. The assassination threat, said one official, "accelerated our push" on Libya.

Analysts with access to security information now say the plot has apparently been suspended, at least temporarily, although the White House insists there has been no diminution of the threat.