The Moscow correspondent for U.S. News and World Report said today he was drugged by a group of Soviet officials who then manhandled and sexually threatened his wife in an incident in Tashkent Wednesday.

The U.S. Embassy said it plans to file a formal note with the Foreign Ministry objecting to the treatment of Robin Knight, 35.

The Knights, both British citizens, were in Tashkent on a tour of Soviet Central Asia arranged through Intorist, the state travel monopoly. The correspondent, whose assignment here ends in June, has been attacked repeatedly in the Soviet press for his articles.

"They wanted to discredit me on personal grounds," he said in an interview in his apartment today.

The incident is the most serious involving a foreign correspondent since last year when two American reporters were accused of civil slander. In June 1977, Robert Toth of the Los Angeles Times was arrested and accused of receiving secret information.

In recent weeks there have been new incidents of harassment directed at foreign journalists. This has included Soviet agents filming journalists attending human rights activists' press conferences and several cases of tire slashing.

Knight, the weekly magazine's correspondent here since 1976, said he became violently ill and fell unconscious a few minutes after drinking a glass of vodka offered by a man who said he was a Intourist guide.

Knight's wife, Jean, said the man also attempted to physically force her to accept a similar drink, that he became angry when she refused and then with his friends made sexual advances after her husband collapsed.

Mrs. Knight, the librarian at the Anglo-American School here, said the Soviets refused to aid her husband and that police later spent hours unsuccessfully pressuring her to sign a form acknowledging that he had been arrested or charged with drunken and disorderly conduct.

The couple said the incident occurred at an isolated Uzbek tea house outside Tashkent, where the official, who called himself "zair" and dressed as an Intourist guide, invited them for what he said was his birthday celebration after showing them around the city.

They said they were met at the restaurant by three other men and two women who identified themselves as guides. After a 2 1/2-hour wait for the meal, during which the Soviets served bread and made vodka toasts which Knight drank and his wife declined, the couple said they were offered special glasses to toast their dinner's arrival. Knight said he drank it, immediately felt ill and went outside where he collapsed unseen on a patio.

Mrs. Knight, 29, said that meanwhile, the men began pawing her and that she ran screamin from the room and discovered her husband outside, violently ill, and unconscious.

With the help of some elderly Uzbekis, she arranged to get her husband back to the city, where they were greeted at the hotel entrance by two policeman who tried to drag Knight off. She said she wrestled him free and with the help of some Americans who happened to be staying at the hotel got him inside where the Soviets then dumped him in an Intourist office and began interrogating her.

She said after some hours, the police allowed her to call the American Embassy in Moscow for advice, and that later that night, the Soviets allowed her to take her husband to their sixth-floor room, where a plainclothesman sat vigil nearby. The officials never mentioned the arrest form again and the couple flew back to Moscow Thursday.