The concert at the Renwick Gallery, with mezzo Renata Babak, baritone Nikita Wells and pianist Frank Conlon, will be at 3 p.m. Sunday rather than 2, as reported in yesterday's Weekend section. The gallery will open at 2:30 for concert-goers only, and seating will be on a first-come, first-served basis.

Soviet officials have decided to close the current and very popular Renwick Gallery exhibit of Russian art tomorrow evening -- nearly a month and a half before its scheduled end -- because they apparently are offended that opera singer Ranata Babak, a Soviet defector, is to perform there on Sunday.

"For us to have this person," a Soviet Embassy spokesman said yesterday in reference to the mezzo-soprano, "singing near a portrait of Pushkin, would be like having Benedict Arnold singing near portraits of George and Martha Washington."

Renata Babak and baritone Nikita Wells, both with the new National Lyric Opera Company, are scheduled to perform various 19th-century Russian songs selected to complement the gallery's exhibit of 19th-century art, which has never been seen in the United States before this traveling show.

Babak, a Ukrainian who defected in 1973 when she was in Italy with Moscow's Bolshoi Opera, has lived in the U.S. several years. Last January she and Metropolitan Opera principal bass Paul Plishka gave a concert under the auspices of the National Fine Arts Foundation in support of human rights.

"A defector -- whom we call a traitor -- has no place near the exhibit," the Soviet spokesman said. "She certainly has no right to be close to these very sacred relics of Russian culture."

"Traitor? What traitor?" Babak said yesterday in response to the embassy spokesman's statement. "They are the traitors -- traitors to their own people. I love my people, but they live in misery."

The spokesman also said, in reference to the museum, that "these people must have known."

"Certainly, when the exhibit was booked, we had no idea who would sing," said Charles Blitzer of the Smithsonian, under whose jurisdiction the Renwick operates. He explained that the scheduling of such performances is done by the Smithsonian's Division of the Performing Arts.

The exhibition cancellation "was not a total surprise," said Blitzer. He talked with Soviet, cultural counselor Anatoly Dyuzhev on Monday. The show's organizer, Barbara Shissler, was notified Wednesday that the exhibit, sponsored by the Ministry of Culture of the U.S.S.R. and the Committee on Institutional Cooperation, would be pulled out early.

Blitzer would not reveal exactly what the Soviets told him. But he did say that they discussed the concert and the exhibition: "The conversation I had with them was civil and courteous. I'm not in a mood for blaming anyone."

Nikita Wells, one of Babak's students, said yesterday that Blitzer had told him Tuesday that the Soviets would allow the exhibit to remain if the concert were moved. "Blitzer told us, 'It's up to you'," said Wells. "It was so late -- there could be no new ads. It would have been ridiculous to move. I think it's petty."