A Soviet seaman who twice jumped ship into the Mississippi River last month apparently cut his wrists after U.S. immigration officials returned him to the vessel, a State Department official told a Senate subcommittee yesterday.

Assistant Secretary of State William M. Woessner said the captain of the Soviet grain freighter Marshal Konev told U.S. officials that the sailor, Miroslav Medvid, had slit his wrists, and that American doctors who examined Medvid on Oct. 28 and 29 confirmed that his wrists had been cut.

"The Soviets said Medvid had cut his wrists himself after he came back on the ship," Woessner testified. "But the doctors found the cuts were not health-threatening and did not create any problems for the interviewing process."

Asked whether there was indication of a suicide attempt, Woessner said, "I don't know."

After the Oct. 29 interview, Woessner said, officials "concurred that the U.S. should allow seaman Medvid to return to the Soviet ship."

Woessner testified before a Senate Judiciary subcommittee hearing called to examine the government's handling of the Medvid affair, which began when he first jumped ship Oct. 24 and continued yesterday, with the freighter still anchored near New Orleans, apparently awaiting a shipment of grain.

In a related development yesterday, a federal appeals court here refused to order the detention of the Soviet ship, which is scheduled to depart Friday. A three-judge panel, acting on a motion brought by the Ukrainian-American Bar Association, said that while the government had mistakenly returned Medvid to the ship the first time, it had remedied the error by retrieving the sailor for another interview, during which proper procedures to determine whether he wanted political asylum were followed.

In that second interview, the panel said, "Medvid steadfastly and consistently stated that he wanted to return to the U.S.S.R., ultimately signing a written statement confirming his wishes. The procedures were, in a word, thorough and studied . . . no rush to judgment, but to the contrary there was a continued effort over several days and on U.S. territory to ascertain Medvid's true wishes."

Two Border Patrol officials decided to return Medvid to the freighter hours after he swam ashore on Oct. 24 because they did not think he wanted political asylum, Immigration and Naturalization Service Commissioner Alan C. Nelson testified yesterday in the government's first formal recounting of the events that began then.

"The agents made the determination that he was not seeking asylum but was clearly a disaffected crewman," Nelson testified. "There were errors in the performance of the INS officers who processed Mr. Medvid's request for asylum."

Nelson said he was "not necessarily disputing" the testimony of Irene Padoch, who interpreted for Medvid and one of the two Border Patrol officials by telephone that night. Padoch testified that an official twice asked her whether Medvid wanted political asylum. Both times, she said, Medvid responded "yes" without hesitation and she conveyed his answer to the official.

"There's an honest difference of opinion on what happened," Nelson said, adding that the telephone connection was not always good and that the conversation was a "very lengthy one.

"The two agents involved said they made a conscious decision that it wasn't an asylum claim being made and they thought that ended the matter."

The officials then phoned the ship's agent in Louisiana, who tried to transport Medvid on a ferry to the freighter. But Medvid jumped into the water again. He was plucked out by Soviet sailors, according to Nelson.

Nelson said the Border Patrol officials exercised "poor judgment" because Medvid's Soviet citizenship should have raised questions in their minds about his intentions. In addition, Nelson noted, "if there had been a question because of the interpretation or the telephonic connection," the officials should have insisted that he stay in the United States until morning, when another interview could have been held.

Nelson said the officials failed to tell a superior about the case. The INS learned of the case the next day when they were contacted by a friend of Padoch, Nelson said.

INS officials then phoned the State Department, and U.S. officials rushed to the ship that night, Nelson said. INS officials on the ship said Medvid was "in bed and appeared to be sedated," according to Woessner.

In response to questions, Woessner said it was at that time that officials noticed that Medvid had "cuts" on his wrist. Soviet officials said the cuts were self-inflicted, Woessner said.

The next day, Oct. 26, a U.S. Navy doctor examined Medvid on the ship and found he did not appear to be under the influence of drugs. On Oct. 28, Medvid was transferred from the ship to a Navy facility on shore, examined by American doctors and a psychiatrist, and ultimately returned to the Soviet freighter at his request.

In New Orleans yesterday, another federal court suit was filed seeking to prevent the Soviet grain freighter from leaving here until the sailor has appeared in court to answer questions about whether he wants to defect.

Meanwhile, a group of Ukrainian-Americans said they would try to slow the Marshal Konev if it tries to leave the United States.

Special correspondent Charles Fishman contributed to this report.