As the State Department continued its efforts to persuade U.S. sport officials to boycott the Moscow Olympics, a department spokesman yesterday charged the Soviets with launching a major countercampaign to prevent a worldwide boycott.

State Department spokesman Hodding Carter said the Soviets "clearly are launched on a major campaign" to counteract the U.S. call for a boycott because of the Soviet invasion of Afghanistan.

Carter also called the Soviet's assertion that they do not mix politics and sports "atrocious nonsense," citing the Soviets'refusal to participate in the past sports events for political reasons and official propaganda on the selection of Moscow for the summer Games.

The Communist Party handbook for the activists, Carter said, claims "in effect that the selection of Moscow as site for the olympics is a sign of world recognition of the correctness of Soviet foreign policy."

Noting that the Soviets had boycotted the Olympics until 1952, Carter added, "They have withheld participation in events in Korea and Israel on political grounds. They were expelled from Davis Cup competition because they walked out on political grounds. They refused to play in Wimbledon in 1977 because, as their coach said, 'It is a political thing.'"

Carter also accused the Soviets of falsely claiming that more than 100 nations have agreed to compete in the Games.

According to department figures, 30 countries -- and 19 of their national Olympic committees -- have agreed to boycott. Another 22 countries have privately indicated they are leaning toward a boycott.

Criticizing some of the remarks of Vitaly Smirnov, the chief Moscow Olympic official hyping the Games on the talk-show circuit in this country, Carter remarked, "It is unfortunate that the U.S. government is incapable of getting its point of view across on Soviet television or in Soviet publications.

"Indeed, the entire set of assertionsby the Soviet Union on the question of the Olympics and our desire that theworld not reward aggression always fails to mention one word -- and that word is Afghanistan.

"Nowhere in any of their discussion is there any mention of the reasion, the rationale for our position -- that participation would be a fundamental error and against our national security interests."

That is the same message the Carter administration attempted to convey on Thursday to representatives of some of the U.S. national governing bodies for Olympic sports who may be asked to vote on a boycott issue next Saturday in Colorado Springs.

The national governing bodies accountfor 71 percent of the votes in the U.S. Olympic Committee -- which decides the participation question -- and the administration has been courting them heavily to ward off the mounting opposition to a boycott.

About 44 officials representing 19 ofthe 32 national governing bodies were briefed at the State Department on Thursday by Defense Secretary Harold Brown, Deputy Secretary of State Warren Christopher, White House counsel Lloyd Cutler and others.

The department is planning another briefing, which Secretary of State Cyrus Vance will head, on Tuesday forthose who could not attend Thursday's closed session.