The Libyan government said today that the early-morning dogfight between its warplanes and U.S. F14s had begun when eight U.S. fighters "ambushed" two Libyan planes, and claimed to have downed one F14 after a "provocation that endangers world peace."

Anti-American rallies were held and broadcast along with propaganda statements at Tripoli airport, and during the afternoon, the government station cut into the airport's public address system with a strident call to " . . . confront the arrogant American attack . . . the entire Libyan people will now face up to the American imperialists."

Neither the broadcast fragment nor the government statement mentioned the loss of the two Libyan planes in the air battle.

However, a Libyan official in London, press spokesman Omar Sudani, later confirmed that the planes had been shot down, United Press International reported. In Washington, Pentagon officials denied that an F14 had been shot down.

After delays in all outgoing flights, apparently because Mediterranean air space was closed by the fighting, passengers at the airport were allowed to depart normally.

The air battle was the climax of many days of rising Libyan-U.S. tension, during which Col. Muammar Qaddafi's regime had grown fearful of a coup attempt with outside support, particularly because Qaddafi is currently traveling outside the country. The government had warned Libya's people of an attack by Egypt, with cover from the United States.

Qaddafi learned of the clash in Aden, the capital of Soviet-supported South Yemen, where he was conferring with South Yemeni and Ethiopian leaders on formation of a new anti-U.S. front. "The United States," Qaddafi declared, according to Aden and Tripoli radios, "will be responsible for any collapse of peace in the Middle East."

Qaddafi called on Libya's other allies and partners -- Syria, the Palestine Liberation Organization (PLO) and the "Socialist camp," meaning the Soviet Union and its allies -- to meet "Egyptian and American provocations."

About two hours before the air encounter, Libya's director of overseas information, Khalifa Azzabi, told this reporter in his office here: "It looks as though something very serious is being prepared against us by America and by Sadat.

"We hope this is not as serious as it looks," Azzabi said. "Because if the Egyptians and you now move against us, it will not be a short affair as it was before. The fighting will go on until one side or the other wins."

"There have been serious Egyptian troop movements on our borders with U.S. support and in the Sudan also for some days now," Azzabi said. "And we hear from Newsweek magazine that the U.S. 6th Fleet is heading our way." Azzabi was referring to the magazine's Aug. 18 report of the U.S. naval maneuvers in the Gulf of Sidra north of Libya's coast that eventually triggered today's clash.

About five days ago, Libya announced that it would hold its own air and naval exercises in the region of the Gulf of Sidra, all of which it considers its own territorial waters and air space. It warned navigators and pilots away from the area in what was interpreted in neighboring countries as a somewhat unusual notification.

One possible reason for the Libyan sensitivity about the area has been indicated by Libyan emigres, who say that the town of Syrte near the middle of the Gulf of Sidra coastline is not only Qaddafi's ancestral home, but also harbors sensitive Libyan installations. According to the emigres, including former Libyan ambassador to India Muhammad Mugarieff, a site near Syrte is being prepared for a nuclear power station that Qaddafi has ordered from the Soviet Union.

In addition, Qaddafi reportedly has prepared an underground command post, protected by bunkers and missile installations, in Syrte in case of a coup attempt. A Soviet-made Libyan submarine, outfitted as a floating command post for Qaddafi to use in emergencies, is said to be berthed nearby.

In the days since the competing naval and air exercises in the gulf were announced, Libyan newspapers and broadcasts have repeatedly charged that joint Egyptian-U.S. military action against Libya was discussed or agreed upon by Sadat and U.S. officials during Sadat's stay in Washington last month.

One of the estimated 1,500 U.S. oil company employes working in Libya, who asked not to be identified, told this reporter: "Ever since publication of the Newsweek story in July that the U.S. planned to overthrow or assassinate Qaddafi, the Libyans have been paranoid about the United States."

The Newsweek report was denied by the administration. But Omar Dellal, a senior Libyan political analyst in Libya's Foreign Liaison Bureau, said two days ago that Libyan leaders were "all worried that the Newsweek report was true, and that U.S.-Libyan relations will take a turn for the worse. We hope against hope that this is not true, but the signs have been growing stronger since you expelled our People's Bureau the Libyan embassy from Washington last June."

The State Department also called in executives of the major U.S. oil companies operating in Libya in May and asked them to reduce their personnel in Libya as soon as possible. The 2,000 Americans still in Libya in May were considered potential hostages if there was some dramatic development in Libyan-U.S. relations.

The companies, whose oil imports from Libya make up 10 percent of total U.S. foreign supplies, protested that they had important contracts to fulfill and could not easily remove personnel from Libya without harming their operations. However, Libya's insistence on demanding high oil prices and the world oil glut earlier this year have caused several of the American firms to halt or cut back on Libyan crude oil.

An American technician with Occidental Petroleum, a major oil operator in Libya, said that Occidental had cut back its production in Libya "by almost half," and had somewhat reduced its staff. However, it was still the company's general policy to keep its U.S. and European employes in Libya on the payroll, even if there was less for them to do.

Although the companies are reported to have cut strengths from 2,000 in May to about 1,500 American personnel in mid-August, there was no sign of any panic among the companies here before the air battle. "We would like to know," the Occidental man said, "just what the U.S. government has in mind to do here."

When I arrived at Tripoli Airport Aug. 16, Western Europeans and the one or two American visitors were being treated routinely at customs stations, without special attention or discrimination.

I have been generally courteously and kindly treated here by ordinary people and by officials. When stranded in downtown Tripoli without a taxi at night, I was driven seven miles to my hotel by the director of Tripoli's newest hospital. The hospital director did not inquire as to my mission or nationality -- he was simply helping a foreigner in need.

The hospital, however, was plastered with posters showing the letters U.S.A. -- in the shape of a revolver pointed at Libya.