The Kremlin signaled reservations about the policies of Polish Communist leader Wojciech Jaruzelski today by publishing a compilation of letters from Soviet citizens expressing outrage and anxiety at developments in Poland.

The letters in Pravda, the Communist Party newspaper, clearly indicated Soviet suspicion of Jaruzelski's attempts to negotiate a compromise with the independent trade union federation Solidarity and Poland's Roman Catholic hierarchy.

But the criticism was given a relatively milder form by being presented as a reflection of popular sentiments rather than an authoritative commentary.

Nevertheless, the compilation of letters seems to constitute the first public criticism of Jaruzelski and Moscow's assessment that his policies are not as decisive as originally hoped for.

Thus far, Jaruzelski has been treated gingerly in the Soviet press, which has dropped all criticism of Poland since he replaced Stanislaw Kania as party leader.

Jaruzelski's meeting last week with Lech Walesa of Solidarity and Roman Catholic Archbishop Jozef Glemp has not been reported here. Nor has there been any public discussion of the latest meeting of the Polish party Central Committee, another indication that Moscow regards its outcome as unsatisfactory.

Pravda today gave no indication when the numerous letters were written. Virtually all the criticisms suggested they had reached the newspaper before Gen. Jaruzelski took over the party post.

A common theme of the letters was outright condemnation of Solidarity. Their writers call on Poles to back their party in the current crisis.

Another theme is Poland's experience in World War II and the fact that 600,000 Soviet soldiers had died to free Poland from Nazi Germany.

"The time has come for real Polish patriots to decide who is a friend and who is an enemy of the country," one writer said.

Another wrote: "How can it be that Poles, having covered such a difficult path in history, have entrusted themselves to enemies in the ranks of Solidarity who are fed by the CIA? Don't be fooled by the destructive propaganda of Solidarity. Remember how the fascists hounded you with dogs, how they led you away to be shot, smothered you in gas chambers."

The letters as compiled by Pravda appear to reflect genuine popular feelings about Poland. Western diplomats here speculated, however, that their publication at this time was designed to bring new pressure on the embattled Polish Communist leadership to take firmer action against the union.