The Soviet Union charged yesterday that Arkady N. Shevchenko, the highest ranking Soviet official at the United Nations, was being held "under duress" by American intelligence agents, and demanded that he be returned home.
A statement issued by the Soviet U.N. mission said that the Soviet government had lodged a "strong protest" with the Carter administration over the "detestable frame-up" of Shevchenko.
The State Department, which announced Monday night that the 47-year-old Shevchenko had left his post at the United Nations and informed the U.S. government that he did not intend to return to Moscow, tersely denied the Soviet allegations.
"The United States in no way attempted to influence him in his decision," a State Department spokesman said.
Reports from numerous quaters yesterday suggested that the entire case is highly sensitive and far more complicated than has thus far been officially admitted.
The sharpness of the Soviet statement and extreme reluctance of U.S. officials to discuss the matter also raised fears that Shevchenko's unexpected act could adversely affect the entire spectrum of U.S. Soviet relations, particularly in the arms control area.
In Washington, Soviet Ambassador Antoliy F. Dobrynin met yesterday with Secretary of State Cyrus Vance and the Shevchenko affair was reported to have been discussed.
Ironically, Shevchenko, as U.N. undersecretary general for political and security affairs, was in charge of preparations for next month's U.N. Special Session on disarmament.
Efforts were under way to reach a breaktrough in the U.S Soviet strategic arms limitations talks that would enable Soviet President Leonid Brezhnev to join other heads of state here at the disarmament conference, and give Brezhnev the opportunity to meet for the first time with President Carter.
American sources said privately that Shevchenko's defection "is the last thing we needed at this time," and Shevchenko's New York lawyer, Ernest Gross, added: "I sure hope they don't want to make a U-2 thing out of this."
The diplomatic furor that followed the downing of an American U-2 spy lane over the Soviet Union in 1980 resulted in the cancellation of a summit meeting between Nikita Khrushchev and President Eisenhower.
The Soviet statement yesterday was Moscow's first official reaction since Schvchenko, 47, indicated privately last Friday that he would not return to the Soviet Union on an official visit as requested by his government.
Evgeny F. Lukyantsev, second secretary of the Soviet U.N. mission, said Shevchenko "had a drinking problem," and added that it was "quite possible or CIA have caught him."
"Circumstances surrounding the disappearance of A.N. Shevchenko leave no doubt that he has become a victim of a premidetated provocation and that the U.S. intelligence services have been directly involved in this detestable frame-up," the Soviet statement said. "It is also clear that at present he is in the hands of those services under duress, and unable to act on his own.
"In connection with this outrageous provocation the Soviet Union has registered a strong protest with the government of the United States and demanded that Soviet citizen A.N. Shevchenko be returned to the U.S.S.R."
Gross promptly rejected the Soviet statement as "tendentious." The lawyer said Shevchenko met Sunday night in Gross' office with two senior Soviet officials to demonstrate that he was acting of his own free will. A Russian-speaking State Department officer was also present as an observer.
Other sources said one of the Soviet present was Oleg Troynovsky, the Soviet ambassador to the United Nation.
Meanwhile, the Soviets moved vigorously to force the ouster of Shevchenko from his U.N. post. If dismissed by the United Nations, Shevchenko, United States as a member of the U.N. Secretarist, would lose his special status and would be forced to seek political asylum if he wished to remain in the country.
Senior U.N. officials said it would be "only a matter of days" before Shevchenko is removed from the position. The Soviet ambassador to Britain discussed the matter Monday with U.N. Secretary General Kurt Waldheim, who was then in London. Weldheim is currently visiting several European countries.
Over the past two decades, Shevchenko has earned a reputation as an arms control specialist and is said to be intimately familiar with Soviet positions on various issues including those involving strategic arms. His defection may force Moscow to reshape many of these positions.
His lawyer Gross, who once served as a U.S. delegate to the United Nations as well as an assistant secretary of state, emphasized yesterday that his client had no intention of seeking political asylum here.
He said Shevchenko is currently residing with "friends" in the New York area, and that he has been given police protection.
The lawyer said that Shevchenko had turned down the Soviet government's request that he travel to Moscow because he felt it was "inappropriate" for him to do so. But Shevchenko's decision was motivated by "his attitude toward the Soviet Union," Gross said, adding that he was not at liberty to discuss this point further.
A ranking U.N. official said that when Shevchenko advised Waldheim's office that he was taking leave from his post last week, he instructed U.N. security officials to seal his office "because he feared his govenment may plant certain things there to incriminate him."
"The Russians are running scared," another U.N. official said. "Shevchenko is the biggest fish that the U.S. has ever caught. Can you imagine what could happen if he gave all his information to the Americans?"
The incident is expecially sensitive because the Carter administration is about to make a major effort to complete a SALT agreement with the Soviets. Vance is scheduled to visit Moscow next week to conduct a new round of talks.
The incident recalled the situation that arose in 1968 when Svetlana Alleluyva, Stalin's daughter, defected in India and inadvertently obtained a U.S. entry visa as a result of a breakdown in communications between New Delhi and Washington.
A senior U.S. official recalled recently how President JohnsoN, who was preparing to begin Strategic Arms Limitation Talks with Moscows, raged furiously about the issuance of the visa, fearing that it would spoil his plans.
The SALT talks eventually opened under the Nixon administration in 1969.
Shevchenko's lawyer, Gross, yesterday scofted at allegations that his client had a drinking problem, or was involved in a liaison with a New York woman.
Gross said that "on the basis of my observations, he is perfectly sober and he is concerned about his wife - he is not sure that she left of her own free will."