The official Soviet news agency Tass accused the Polish government today of "another concession to the counterrevolution' in its release from prison, pending trial, of a leading anti-Soviet Polish dissident.

As the Kremlin intensified its most recent press and radio campaign against Poland's government and party, Tass also repeated its endorsement of the hard-line Katowice Forum in Poland, which has accused the country's Communist Party leadership of factional disputes and indecision that endanger is authority.

The new tough Soviet criticisms of the Polish leadership resemble those made at other critical periods in the past year of labor turmoil, but it is not clear if they are intended simply to intimidate the Polish leadership or to prepare Soviets and others for a possible military intervention.

Many analysts here think the Kremlin's latest denunciations of what it refers to as "the situation in Poland' may be a serious attempt tol pressure Warsaw into postponing its Communist Party congress, which is scheduled for July and is expected to take further steps to liberalize the party and enact democratic reforms.

The Tass accounts, read on radio and television for maximum impact internally, asserted that "many Communists . . . support the Katowice Forum propositions. On the other hand, a campaign of attacks on the forum has been launched, first by the rightwing leaders of Solidarity [and] the leaders of some party organizations act with them."

For much of the week, the Soviet news media have carried favorable accounts of the forum formed by Stefan Owczarz, a leading Polish hardliner, in Katowice. The group has accused the Warsaw leadership of splitting into factions, exercising ineffective leadership and doing serious damage to the party in the past 10 months.

Tass charged today that "a number of mass media" in Poland, including newspapers that "have long attacked the party from revisionist positions" have denounced the Katowice Forum.

It described the Polish authorities' decision to release Leszek Moczulski and three other members of a group called Confederation of Independent Poland, as "the latest retreat to counterrevolution." Moczulski, whom the Soviet press has repeatedly denounced, had been in pretrial detention since last year but demonstrations and hunger strikes by students and workers throughout Poland in recent days had demanded the release until the trial takes place.

In both these cases, Moscos's complaints amount to public polemics against the Stanislaw Kania leadership for bowing to public pressure to release Moczulski and for allowing open critism of the Katowice hardliners. Moscow so far has taken no notice of the Polish leadership's firm rejection of the forum's views, another sign of Kremlin ire.

In the view of many foreign analysts here, these and related denunciations add up to a significant escalation from past peaks of Moscow's criticism. Although there are no credible reports available here that Soviet and Warsaw Pact forces on Poland's borders have returned to the high state of readiness of last August and December, senior Western diplomatic sources indicated the seriousness with which they view the new propaganda campaign by saying today they "wouldn't be surprised" if new pact military maneuvers began sometime before the crucial Polish party congress, scheduled to begin July 14.

[State Department spokesman Dean Fischer said in Washington that the United States has received "unconfirmed reports" that military maneuvers may soon begin in and around Poland. Fishcer said there is no sign of any military activity in the vicinity of Poland and no evidence to confirm that Warsaw Pact maneuvers will take place anytime soon. He said the United States "will monitor the situation closely."]

Even if maneuvers suddenly begin, unofficial Soviet sources as well as many East European and Western diplomats continue to hold to the belief that Moscow knows the stakes in any direct intervention are critically high and that this knowledge stands as the chief deterrent to the kremlin's use of force.

If the Kremlin could gain time by gaining postponement of Poland's party congress, some of the diplomats and other sources say, it might yet find a way to achieve enough leverage inside Poland to stem the tide of political change without resort to force.

Precisely how the Soviets could do this is unclear but the Tass backing for the Katowice Forum suggests one way of bolstering conservatives within the badly split party at the expense of the reformers. At the same time, economic problems and spreading food shortages help to erode support for Kania in ways Moscow may yet seize upon.

Meanwhile, a senior Western source said today, it seems clear that "if the Poles get their elections, a new government and a new leadership, it will be even harder for Moscow to intervene after the fact."

This makes it crystal clear, he said, that for Moscow "a moment of truth is coming fast."