The long-awaited reunion of Virginia history professor Woodford McClellan and his Soviet-born wife has hit a snag, with Soviet authorities saying they need more time to decide whether to allow Irina McClellan's 26-year-old daughter to emigrate with her.

McClellan, 51, who lives in the tiny town of Ivy and teaches Russian history at the University of Virginia, has waited 11 1/2 years for the reunion with his wife that last week appeared imminent.

On Sunday, Irina McClellan, 47, was told that she is free to emigrate to the United States, but that her daughter's visa application would need further review. She told reporters in Moscow on Monday that she would not leave without her daughter. "I'm not going to divide the other part of my family," she said.

"She will not abandon her child. I back her totally," an anguished McClellan said yesterday.

"I'd like an explanation from the Soviet government," he said. "They are making people sweat blood."

The daughter, Yelena Kochetkov, a seamstress who lives with her mother, suffers from a serious ulcer ailment and has twice undergone surgery for the problem, most recently last March. Woodford McClellan is her stepfather.

A State Department official said that Irina McClellan and a U.S. Embassy aide went to a Soviet passport office in early December and were told then that both mother and daughter would be permitted to emigrate to the United States after submitting visa applications.

The State Department issued a statement yesterday saying: "We urge the Soviet authorities to move quickly to resolve the McClellan case by granting exit permission to Mrs. McClellan's daughter."

Irina McClellan is one of 10 persons with ties to the United States who are to be allowed to leave the Soviet Union. U.S. State Department officials said they received the list of names shortly before the U.S.-Soviet summit in Geneva in November.

Two of the women on the list, Helle Frejus and Tatyana Bondareva, have already been reunited with their husbands here.

Monday, U.S. officials said the Soviet Union told them another 36 persons with relatives in the United States would be allowed to leave.

McClellan met his wife in 1972 when he accompanied a Canadian tour group to the Soviet Union to lecture on Russian history. He saw her again during three trips to the Soviet Union in 1973, and the couple married the following year.

They have lived apart since the summer of 1974, when Soviet authorities refused to allow Irina McClellan to return to the United States with her husband.

Although McClellan's hopes for a reunion with his family have been raised and dashed time after time over the past decade, the Soviets' reversal on his stepdaughter's emigration took McClellan by surprise.

"I am perplexed and astonished that the Soviet Union would revoke a promise they made in the presence of an embassy official," he said. "Why are they tormenting three people? Why are they prolonging this ordeal?"

McClellan said he had expected his wife and stepdaughter to reach the United States this month, but said his wife has been told the Soviets' new review of Kochetkov's visa application could take months.

"That's ominous," he said. He fears the delay could prevent his wife from being able to leave the country. "Her exit visa will only be valid for a short period of time," he said.

Still, McClellan's hopes were somewhat buoyed after talks with State Department officials yesterday. He was assured, he said, that "the U.S. government isn't going to take this lying down."

McClellan believes there is no reason for the Soviets to prevent families of Americans from leaving. "It's a cost-free gesture on their part," he said. "It just means letting a few people live in peace and obscurity."