The Kremlin seems to be signaling a very modest mellowing of its tone toward the United States. The signal, if that is what it was, came Monday with Soviet Foreign Minister Andrei Gromyko's first major review of Soviet foreign policy since the new Soviet leader, Konstan-tin Chernenko, came to office.
The Soviet Union, Mr. Gromyko said, ''stands for even and normal relations with the United States,'' provided such relations are based on ''the principles of equality and equal security, mutual respect for legitimate interests, and noninterference in each other's internal affairs.''
Both in the style of delivery and in the content, Gromyko's remarks appeared to differ markedly from his last major foreign-policy speech, made at a conference in Stockholm last month. The tough, uncompromising, anti-American rhetoric - although still present - seemed to have been played down somewhat.
Although Gromyko did not depart from known Soviet positions, his speech - made in the Byelorussian city of Minsk - did differ in tone from other recent ones. In the version released by Tass, the official Soviet news agency, there was no Soviet demand to remove new US-supplied NATO missiles from Western Europe - a familiar litany in speeches by the Soviet leadership in recent months.
Instead, Gromyko stressed that ''the USSR . . . stands for reaching agreements on the limitation and reduction of nuclear armaments in accordance with the principle of equality and equal security.''
To be sure, he had some strong words for the Reagan administration.
He blamed the United States for escalating the arms race by stationing new missiles in Europe and said the US caused the failure of Geneva negotiations aimed at limiting nuclear arms on the continent.
He said the US administration had ''done a good deal to disrupt, and, moreover, to destroy what had been achieved by its predecessors. Naturally, it is easier to destroy, to overturn agreements concluded by others. This takes no special effort. What it takes is merely a good measure of recklessness and irresponsibility.''