The Soviet authorities, in a surprise move, say they have decided to meet the demand for which dissident physicist Andrei Sakharov went on hunger strike nearly three weeks ago.
If implemented, the stated decision to allow Liza Alexeyeva to join Dr. Sakharov's stepson in the United States would be a sharp departure from past Kremlin policy on political dissidence - and from the Soviets' public position on the Sakharov protest fast.
In a development suggesting uncertainty as to when and whether Miss Alexeyeva would actually be allowed to leave, she was told late Dec. 9 that the timing of her departure would depend partly on her ''behavior toward foreigners.''
She said she was advised, in particular, not to ''cause anti-Soviet noise to be made abroad,'' a clear reference to her meetings with Western reporters here since Sakharov and his wife began their hunger strike late last month.
Miss Alexeyeva, summoned by the KGB security police for a mid-afternoon meeting Dec. 9, says she was told ''a decision had been taken yesterday to give me an exit visa.''
She was told that the Nobel Peace Prize winner had been informed of the decision and had given up his hunger strike. Sakharov was now feeling ''better, '' KGB official Alexander Baranov reportedly told her. But when asked about the scientist's wife, the official could offer ''no further information.''
Miss Alexeyeva -- her face taut with fatigue -- told reporters afterward, ''I don't understand. . . . This is very strange.'' Friends spoke of the Soviet move with a mix of relief and skepticism.
Only days earlier, the Soviet government newspaper Izvestia denounced the Sakharovs' fast as a ''provocation.'' The paper charged that the Sakharovs had been ''brainwashing'' the young woman and ''urging her to leave the USSR.'' Izvestia said her ailing parents were against such schemes, and added: ''Our laws say that children must take care of their disabled parents, advanced in years.''
The article ended with the brief announcement that the Sakharovs -- who began their protest Nov. 22 in Gorky, where the scientist has been exiled some two years -- had been taken to the hospital for ''preventive care.'' Friends were convinced they had been hospitalized against their will. Miss Alexeyeva expressed fears they were being force-fed.
Diplomats took the hospitalization as a reflection of genuine nervousness over the Sakharov protest at a time when the Kremlin is seeking better ties with the West. Since the hunger strike began, the Soviets have come under wide criticism from prominent Western figures, including even the generally pro-Soviet chief of the French Communist Party.
A small minority of foreign diplomats here speculated the Kremlin might bring itself to bury its preoccupation with military security and banish Dr. Sakharov to the West, despite his involvement more than two decades ago in development of the Soviet hydrogen bomb.
The unanimous assumption has been that Miss Alexeyeva -- married to Dr. Sakharov's stepson in a proxy ceremony Moscow does not recognize -- would be denied an exit visa.
By late afternoon Dec. 9, even pedestrians who usually tune in to Western radio broadcasts had not yet heard of the reported Soviet turnaround. Told of it and asked for comment, they reacted with surprise.
Some had read the Izvestia article.''Well, we are good to be rid of anti-Soviet people who want to leave,'' said one man.
But there was open puzzlement in most of the replies.
''Yes, this is strange,'' said a young man in the familiar Russian fur hat. ''But who knows? Politics is politics. . . .''
A transport worker paused, knocked the season's first good snow from his boots, and declared: ''It is hard for us in the working class to comment on such matters. You must go to a higher level.''