U.S. Ambassador Jeane Kirkpatrick today dismissed as "lies" Libyan charges of American aggression, and accused Libyan leader Col. Muammar Qaddafi of personally conducting a "virulent hostile foreign policy" through the use of terrorism and assassination to overthrow rival governments.

In a Security Council meeting called by Libya to air charges of "provocative" U.S. air and naval movements near its borders, Kirkpatrick countered that such movements were necessary because "concentrations of Libyan aircraft . . . were of concern" to neighboring Sudan and Egypt.

Kirkpatrick's statements were the first specific public charge by the Reagan administration, since it moved the aircraft carrier Nimitz to waters near Libya last week, that Qaddafi had moved warplanes into position to threaten the Sudanese government of Jaafar Nimeri.

Four U.S. Airborne Warning and Control Systems (AWACS) were dispatched to Egypt at the time.

The Pentagon said Saturday that the Nimitz was returning to its position off Lebanon, where it had been supporting U.S. Marines, and Secretary of State George P. Shultz declared Sunday that the threat from Libya was over.

Kirkpatrick said the AWACS surveillance planes had been scheduled to engage in a training exercise in Egypt in March and had been dispatched there earlier "because of the situation."

The presence of warships "sometimes seems to have a deterring effect on Libyan adventurism," she said.

But she denied as "false and malicious" the Libyan charges that the American craft had encroached on waters or airspace claimed by Libya.

In opening the Council debate, which was marked by some of the most heated and specific charges made here in recent years, Libyan Ambassador Ali A. Treiki outlined a long list of American actions against Libya and other nations dating back to the Marine landing on the shores of Tripoli in 1805. He denied that Libyan troops had mobilized along the Egyptian or Sudanese border, and insisted that Libya "is a small country that desires to live in peace."

Kirkpatrick responded with the charge that Libya is currently backing insurgent movements for the overthrow of the government in Sudan, Somalia, Chad and other African nations.

She noted that Qaddafi had sheltered the perpetrators of the 1972 Munich Olympic massacre and the 1975 attack on the OPEC meeting in Vienna.

In addition, she said, "the infamous Carlos," the Venezuelan-born terrorist, has operated out of Libya over several years," and Libyan weapons were found on two of his agents captured in Paris last summer.

Less widely known, Kirkpatrick said, were Libyan plots to assassinate American ambassadors in several Middle East countries and at least one European capital. One plot, in November 1981, she said, involved the planting of explosives in the stereo speakers at the American Embassy Club in Sudan, timed to kill scores of people at a Saturday night reception.

After the council meeting, U.S. officials added that at least three African heads of state have reported assassination plots by Qaddafi against them. Neither they nor Kirkpatrick named the countries nor officials allegedly targeted by Libya.

Defending the legitimacy of the U.S. actions to deter Libyan actions, Kirkpatrick said the administration hopes that "more states with aggressive designs on their neighbors will be discouraged, by the lawful response of others, to desist in their unlawful plans."

Sudanese Ambassador Abdel-Rahman Abdalla accused Libya of trying to overthrow his government and "impose a Libyan hegemony on Sudan." He defended Sudan's decision to call for U.S. help, saying that his country had to "use all ways and means to defend itself in cooperation with friendly countries. The American moves were necessary to foil the massive Libyan concentrations," he said.

Egyptian Ambassador Ahmed Khalil, in a brief and relatively dispassionate statement, said that Egypt is "fully committed to defending fraternal Sudan," and that all it wishes from Libya "is to work for peace in the area and the settlement of disputes in peaceful ways."