Seven Western antiwar activists attempted to bring the peace movement to Moscow today but were seized almost instantly when they unfurled a 10-foot banner that said, in Russian, "Bread, life and disarmament."

Although the Soviet news media have been giving publicity to the Western peace movements, Soviet authorities do not condone any spontaneous demonstrations.

Security agents pounced on the West Europeans before they managed to hand out a single leaflet in the Red Square demonstration. The seven, all men who appeared to be in their twenties and thirties, were taken away in police cars and held for several hours.

A Soviet Foreign Ministry spokesman described the incident as trivial. He said the men had been released and would leave the country Tuesday when their tourist visas expire.

Except for a group of Western reporters tipped off in advance by the protesters, the incident attracted apparently no interest from crowds of Soviets and foreign tourists gathered outside the Lenin mausoleum. It took place at 1 p.m. when crowds watch the changing of the guard.

The Soviet KGB security police also appeared to have advance knowledge of the demonstration.

A spokeswoman for the protesters, Anne Brocquemont, said they included two Frenchmen, two Spaniards, two Italians and a Belgian. All except the Spaniards were said to be members of a Rome-based movement that campaigns against military spending and urges more economic aid to the Third World.

Brocquemont, who was not detained, said all had come to Moscow with a group of Belgian tourists.