On Tuesday, a group from the Peace Committee dropped by the U.S. Embassy here, followed by a group from the Women's Committee. On Wednesday, it was the Young Communist League, and on Thursday, a delegation came from the Soviet trade union organization.

One after another, they came to deliver petitions, letters and protests to stop the U.S. nuclear test in Nevada yesterday.

In midweek, the embassy formally sent its own protest to the Soviet Foreign Ministry complaining of political "demonstrations" held on the embassy's doorstep on Tchaikovsky Street.

According to a spokesman for the embassy, the problem was not with what the groups had to say, but how they chose to say it -- unannounced, and accompanied by Soviet television cameras.

The protests here by the official Soviet groups were featured in the press and shown prominently on television. The pictures showed the groups being turned back onto the street, where such spokesmen as writer Genric Borovic made sarcastic comments about tight American security.

An embassy spokesman said the groups were not allowed to enter the main embassy building but that their letters were accepted inside the embassy's entryway.

To U.S. diplomats, the irony of the public fuss over being denied entry to the embassy had nothing to do with American security arrangements.

In this highly security-minded country, about 10 Soviet guards are posted around the embassy to check the documents, and the business, of every Soviet citizen trying to walk in.

But in the case of the visiting peace groups, the policemen waved the delegations in, apparently without question.