The Soviet Union tonight bluntly charged that Solidarity trade union leaders "are deliberately making unacceptable political demands" and that they are trying to become "a political party hostile to the Polish Communist Party."

The accusation was broadcast tonight on the national Soviet news program as a commentary on the talks under way in Poland, and represents a serious new escalation of Moscow's public handling of the crisis. [In Berlin, the official East German news agency ADN reported that "new units" have been brought in to replace forces that began Warsaw Pact maneuvers in and around Poland last week. The report said that motorized units and artillery troops taking part in the exercises "were able to return to their stations after successfully completing their duties and were replaced by new units." ]The exercises, including troops from the Soviet Union, Poland, East Germany and Czechoslovakia, have been extended, reportedly because of Poland's labor turmoil, and have raised fears in the West that the Soviet-led forces may intervene.

The official Tass news agency dispatch from Warsaw further charged that "Solidarity is assuming state functions" because it has placed its own guards around the building where the talks are taking place.

Tass accused top union leaders of "using the continuous strikes to put pressure on Poland's party and government" in an effort to "demonstrate that their government is incapable of normalizing the situation" in the country.

This unmistakably threatening account comes as the Polish Communist Party prepared for a Central Committee meeting Sunday and the Polish parliament planned to meet Monday, with the strike deadline set for Tuesday. Some observers here believe Moscow is using bare-knuckles talk to strengthen conservative elements within the Polish Communist Party who are opposed to the reforms that party leader Stanislaw Kania and his closest aides seem so far inclined to pursue.

In a separate dispatch, the agency complained that the "American administration is meddling in the affairs of the Polish republic," and called this "crude interference." Tass also said that it was "no accident that in West Germany maps are already printed showing Poland within its 1937 borders." After World War II, Poland gained several of its western provinces from Germany while ceding part of its eastern territory to the Soviet Union.

Tass declared that the upcoming nationwide strike was not for economic reasons, and the "the aims of the . . . strike organizers show evidence of their aspiration to demonstrate that they represent a political force directed against the socialist system."

It said the leaders of KOR, the Committee for Social Self-Defense, "are not satisfied" with the government's attempts to normalize the situation, adding that yesterday's four-hour warning strike had cost the Polish economy 2.5 billion zloties, or about $83 million.

The combination of Soviet statements tonight adds grave new pressures to the crisis. The Soviets until recently have indicated genuine backing for Polish party leader Kania, but these dispatches show open Soviet anger over the independent workers' movement's strength and visibility.

Early in March, Moscow reaffirmed the "Brezhnev doctrine" of intervention to maintain communist power in Poland if all other means fail.

Observers here believe that Moscow's requirement is communist political supremacy in the turmoil-ridden nation that will both insure alliance with the Warsaw Pact and guarantee crucial Soviet lines of communication across Poland to Soviet military forces in East Germany.