Moscow — The Soviet Union is stepping up efforts to tie the United States Central Intelligence Agency to the assassination of Indira Gandhi. The campaign, started within hours of the Indian leader's death, appears to have escalated.
Western diplomats here say there is no mistaking that the timing of articles in the government-controlled press, and their placement in Soviet newspapers, is aimed at fanning suspicion of CIA involvement in Mrs. Gandhi's death.
The Soviet charges rely heavily on innuendo and implication, and they have drawn official protests here and in Washington. Nevertheless, they continue.
The emerging Soviet line, repeated in news reports, telegrams of condolence, and official statements on the assassination, is that Mrs. Gandhi fell victim to a ''conspiracy of reactionary forces.'' In the Soviet political lexicon, that formulation clearly means the US.
But Moscow has stopped short of directly blaming Washington or the CIA for the assassination. A Soviet Foreign Ministry spokesman, Vladimir Lomeiko, said India alone should fix the blame for the tragedy.
A series of reports here allege CIA links to Sikh extremists, note that Sikh extremists were responsible for Mrs. Gandhi's death, and then suggest that the CIA will stop at nothing, ''up to political assassinations,'' in pursuit of its aims. Some examples:
* Tass, the official Soviet news agency, claims the CIA and the US State Department ''have carried out a number of operations'' aimed at ''the encouragement of separatism in India.''
* Pravda, the official Soviet Communist Party newspaper, ran a commentary entitled ''Terrorism - the Politics of Washington'' alongside Gandhi's obituary. Pravda also claimed the CIA had been involved in ''recent bloody incidents'' in Punjab state, stronghold of the Sikh separatist movement.
* Soviet television has run reports from India showing demonstrators carrying anti-American placards, along with commentary similarly linking the US with the assassination.
Radio Moscow went even further, suggesting that the slaying of Gandhi was part of a ''chain of conspiracies'' to eliminate leaders of third world and so-called nonaligned nations which refuse to buckle under to Washington's pressures.
The Soviet propaganda effort comes in the face of allegations in the Western press that the Soviet Union's own intelligence agency, the Committee for State Security (KGB), may have been involved in a plot to assassinate Pope John Paul II in 1981.
Meanwhile, the Soviet Union continues to take stock of the political impact of Gandhi's death. In Washington, State Department officials said that Soviet Prime Minister Nikolai A. Tikhonov would likely be head of the Soviet delegation to Gandhi's funeral on Saturday.
A number of Western analysts here in Moscow presume that the Kremlin leadership is satisfied with the succession of Gandhi's son, Rajiv, to the prime minister's post.
A telegram of congratulations sent to Mr. Gandhi by the Soviet government called for ''strengthening and deepening traditional relations of friendship and cooperation with India.''
''You may rest assured,'' the message said, ''of the Soviet Union's readiness to extend assistance to India in further consolidating its economy, in enhancing its international prestige.''
Indira Gandhi was one of Moscow's best friends in the nonaligned movement, frequently infuriating Washington for ''tilting'' in favor of the Soviets. She initially condemned the Soviet invasion of Afghanistan, for example, but later held consultations with officials of the Soviet-backed Afghan government.
India has also been one of the Soviet Union's best customers for armaments, purchasing more than $10 billion worth from 1954 through 1983.
In fact, Indian Defense Minister S.B. Chavan was here in Moscow, for what diplomats believe were negotiations on arms sales, when Mrs. Gandhi was assassinated. He quickly cancelled the rest of the trip and headed home for the funeral.