U.S. and West European governments are keeping a close eye on recently detected signs of unusual military activity by Soviet forces in the western Soviet Union and East Germany that could be aimed at Poland.

Though several U.S. officials said privately yesterday that they do not believe there is an imminent threat of Soviet military intervention in Poland, Secretary of State Edmund S. Muskie reflected U.S. wariness when asked by reporters if he has any sense of danger about the reported Soviet moves.

"Whenever there is a coincidence of political developments," such as those that have been sweeping through Poland's labor force in recent weeks "and these [military] exercises in that area of the world, one would not be wise to overlook the coincidence," he said.

U.S. officials generally are close-mouthed about exactly what the Soviet forces are doing, other than confirming that Western intelligence agencies -- presumably including allied sources in Europe -- have detected signs of unusual activity that began about a week ago.

One senior administration official, who asked not to be identified, said the concern, especially among Europeans, centers on Soviet troop maneuvers now under way that have enough "ambiguity" and "flexibility" about them to suggest they could be turned toward Poland.

Officials said the activity does not involve, at this point, a large buildup of Soviet troops near Poland's borders or movement of troops toward those borders. Rather, they suggested that other unusual activity that triggered the West's caution had to do with signs of a possible mobilization of reserves and with Soviet military equipment, such as electronic gear used for communications and to command and control military units.

One senior official said it is premature to jump to hasty conclusions about Soviet intentions and what the military moves mean. Some Soviet forces are on regular fall maneuvers, but sources said the exercises attracting the West's attention have distinctive aspects to them.

There are no grounds, the senior official added, for a war scare. But economic and political uncertainties in Poland since the strikes that rocked the country and caused a change in Communist Party leadership are viewed here as being far from ended.

"It would be rash to conclude the Soviets are going to intervene, but blind to conclude that they won't," he said.

Another top U.S. expert on Poland said he "wasn't excited yet," feeling that the Soviet actions primarily may be meant as a demonstration of power to Poland's leaders and workers to pressure them to get things under control.

The Soviet Union has about 20 divisions in East Germany, on one side of Poland, and at least another 20 in the western military districts of the Soviet Union, east of Poland.

The Soviets, however, have only two divisions based in Poland and so would need time to make a sizable force ready for combat and move it to the Polish borders. U.S. sources estimate that the West would have two weeks of additional warning time before an actual attack, because such a large mobilization would be difficult for Moscow to hide.

The stakes for Moscow and Central Europe in such an enterprise, however, would be enormous and the results possibly catastrophic.

When the Soviets moved into Hungary in 1956 to put down an uprising there, the Hungarians fought back, although they had little to fight with. And the Soviet-led thrust into Czechoslovakia in 1968 to put down the liberalization movement there met with little resistance.

But it is believed that the fiercely nationalistic Poles would fight the Soviets if they intervened, and that the 15-division Polish army might turn its guns on the invaders.

Polish workers won extraordinary concessions from their communist government with a disciplined and dignified approach, free of violence. Those tactics were designed not to give the Soviets any pretext to intervene. t

State Department spokesman John Trattner yesterday reiterated the U.S. view that the Polish people and government should be allowed to work out their problems on their own. Officials said that Muskie two weeks ago -- before the new activities were detected -- met with a Soviet Embassy official and appealed for Soviet restraint in dealing with Poland.