MOSCOW, JULY 26 -- A group of about 150 Crimean Tatars who conducted an all-night vigil on the edge of Red Square dispersed quietly this afternoon after being promised a meeting Monday with Soviet President Andrei Gromyko.

Hundreds of militiamen closely watched the extraordinary demonstration, encircling the protesters with buses. Demonstrators said the authorities used no force today.

Several hundred Crimean Tatars, most of whom are now living in Central Asia, came to Moscow this week to press for renewed recognition of their ancestral homeland in the Crimean Peninsula. Its status as the Crimean Autonomous Republic was abolished by Joseph Stalin during World War II. Stalin's government accused the Tatars of collaboration with Nazi occupiers and forcibly evacuated about 250,000 Tatar men, women and children to Central Asia in 1944.

On Thursday, the Tass news agency announced the creation of a special government commission, headed by Gromyko, to study their demands. The announcement referred to Tatar collaboration with the Nazis, but said the indictment and eviction of the entire population had been unjust.

After the sit-in broke up, Sofina Dzhemilev, wife of Tatar activist Mustafa Dzhemilev, said the group will continue to press its demands if Monday's meeting with Gromyko does not produce results.

Official handling of the all-night sit-in was viewed by western observers here as unprecedented, showing restraint on the part of the police and security forces and flexibility by political intermediaries. In the past, public protests usually have been broken up by force, with squads of plainclothesmen herding demonstrators away from public places and detaining key figures.

The Crimean Tatars are descended from a branch of the Mongolian army, the Golden Horde, which established a khanate, or principality, on the Black Sea peninsula in the 15th century.

Many passers-by were puzzled by barricades set up at entrances to Red Square, and by the numerous police guarding walkways and intersections. Witnesses said the buses were assembled early this morning.

"They are preparing for tonight's fireworks," one policeman told an inquiring woman who eyed the phalanx of buses. Today was Navy Day in the Soviet Union, and fireworks were displayed this evening.

Several Russians interviewed were unsympathetic to the Tatar demands for a Crimean autonomous republic, recalling the issue of Nazi collaboration and bridling at the demands of an ethnic minority.

"The better people live, the more they want," said one bemedaled war veteran. "If I were in power, I would have them shot."