The Soviet government yesterday accused an American posing as a diplomat in Moscow of involvement in the murder of an "innocent Soviet citizen who stood in the way" of an espionage ring run here by the Central Intelligence Agency.

The charge was leveled at Martha D. Peterson, a former vice consul in the U.S. Embassy here who was described as a CIA agent who transmitted the poison used in the killing. The alleged victim or the spy who carried out the execution were not indentified.

[Sources in Washington confirmed that Peterson, 33, employed by the CLA but declined to comment on specifics of the Soviet allegations.]

The accusation in the government newspaper Izvestia alleged that Soviet counter-intelligence agents uncovered the plot last year when they intercepted Peterson as she was about to transfer espionage gear, including two poison capsules. Concealed inside a fake rock to her unidentified contact. Among allegedly captured items were photographic equipment and money.

"It was found out during the investigation that the poison transmitted to the spy earlier had been used to kill an innocent Soviet citizen who stood in the way of the spy's criminal activities," Izvestia said.

While U.S. Embassy sources refused to comment on the allegations, they said that Peterson worked in the embassy from autumn 1975 to July 1977 and that following her departure she was declared persona non grata by the Soviet government. Officials refused to provide any additional details except to say that she had been "detained briefly" by Soviet police before her departure.

The extraordinary accusations published on the front page of Izvestia appear to be a response to recent American disclosures that Soviet eavesdropping gear had been discovered secreted within the U.S. Embassy chancery here. They also seem to be linked to the arrest in New Jersey of two Soviet citizens accused of espionage.

Izvestia clearly indicated that its revelations came after the "American side" violated an unwritten understanding under which the two sides refrained from publicizing each other's espionage actions.

[Sources in Washington said it was true that the current charges back and forth between Moscow and Washington represent a departure from past practices in which espionage operatives using diplomatic or quasi-diplomatic cover were expelled quickly and without publicity.]

Izvestia's harsh language underscores relations between the two capitals as the Carter administration scrutinizes its basic attitudes toward Moscow and sounds repeated notes of warning of a new strategic arms limitation agreement and Soviet military involvement in Africa.

Over the years, both governments have accused each other of harboring spies among their diplomats and many diplomats have been expelled on espionage grounds.

A trial is now under way in Newark, N.J., involving the two Soviets accused of conspiring to pass U.S. Navy secrets to Moscow.

Izvestia's accusations of CIA poisoning are virtually without precedent. It tied the allegation to an attack on CIA Director Stansfield Turner's congressional testimony saying the CIA no longer condones or supports political assassinations.

"How to tally Turner's public statement with the practical work of his agency?" Izvestia asked.

The long article, mixing sarcasm and contumely with purported facts, leave many major questions unanswered in a confusing pastiche. It was written by Yulian Semenov, this country's most famous spy novelist and author of a recently widely hailed television series about how Soviet agents prevented the United States from making a separate peace with Hitler during World War II.

The article said Peterson was involved in an effort to obtain information and falsify it "to stop detente."

It said she was seized last July 15 after elaborate efforts by her to evade survellance and deposit the espionage rock in an arch of a well-traveled bridge over the Moscow River so it could be retrieved by the annonymous spy.

It said that when she was apprehended "she started shouting, 'I am a foreigner.' Obviously the vice consul was shouting so loudly to warn the spy who was coming to the appointment place about the danger."

The newspaper published two photos, one showing what it described as the contents of the hollow rock and the other of Peterson and U.S. Consul Clifford Gross sitting at a table with items from the rock spread before them.