The officially atheist Soviet Union has begun disstributing, through its embassy here, press releases extolling the vigor of religious bodies in the Soviet Union.

Glowing accounts of the life and growth of both the Russian Orthodox Church and the Baptists of the Soviet Union reached The Washington Post Wednesday, the first such communications about religion from official Soviet sources in at 15 years.

Vladimir Brodetzky, embassy information officer, sent the stories along with two photos of Pimen, Russian Orthodox patriarch of Moscow and all Russia. Brodetzky at first said the move represented "a new drive to distribute such articles," but then corrected himself and said: "I would not call it a new drive-not totally new."

In New York, Lillian Block, managing editor of Religious News Service, said the Soviet Embassy's distribution of articles on Soviet rekuguiys developments appeared to be "a very recent development within the last two months. We never got it before and now we get it regularly.

"Every one [press release] would have you believe that religion is thriving in the Soviet Union. I throw them in the wastebasket."

The articles were from Novosti Press Agency, the official government press agency with Soviet secret police connections.

Both were upbeat and laudatory, and with only a few changes in names and places, much of the material could easily have been mistaken for a handout from an American church publicist.

"The Russian Orthodox Church is preparing for Christmas with renewed vitality," began one.

"'I would like to begin my Christmas sermon to my brethren-in-faith by saying, 'Peace on Earth and good will among men,'" began the other story under the Novosti Press Agency banner, in a quote from Pyotr Shatrov, a member of the presidium of the All Union Council of Evangelic Christian Baptists.

Shatrov, the story explained, "travels a lot around the Soviet Union and abroad and often delivers sermons to Baptist congregations." In these visits, Shatrov explained, he always asks the congregations "about the good things eachone of them has done both in his or her religious and civil life in the past year."

The story explained that "both notions constitute one inalienable whole for the Baptists of the Soviet Union. They do not evade their duties in society and seek to set an example at work." It went on to praise Shatrov's own brother, "Pentecostalist Alexander Shatrov," an engineer who recently won a government award for his work.

Each story boased of churches-"some 30 prayer buildings" for the Baptists-built or renovated, Bibles and other religious literature published, and hinted at growing memberships within the officially atheistic nation.

Virtually all the historic great Orthodox cathderals in the Soviet Union have been turned into museums or used for nonreligious purposes.

While atheism is the official policy of the Soviet Union, the communist country has pointed with pride to the fact that its constitution guarantees freedom of religion. The definition of religion, however, virtually restricts it to ritual and pietistic concerns. Expression of social and political dimensions of religious belief, commonplace to churches in this country, are forbidden.