Cuba's official news agency has labeled U.S. charges about the presence of Soviet combat troops here a "maneuver" by the United States and its "Chinese puppets" and, without directly affirming the charges, has thanked the Soviets for defense assistance.

"The fact that Cuba, thanks to the courage of its sons and generous Soviet military aid, has defended itself during 20 years of North American attacks, sabotage, infiltrations and invasions is well known by Washington leaders from Eisenhower to Carter," said a Prensa Latina commentary last night.

The Cuban government has made no official comment on the charges, made last week by Sen. Frank Church (D-Idaho) and later by the State Department that up to 3,000 Soviet combat troops are stationed here. The charges now threaten Senate ratification of the second strategic arms limitation treaty.

[There has been no official Soviet response to the U.S. charges and the Soviet press had no comment Thursday on Secretary of State Cyrus Vance's statement Wednesday on the seriousness of the troops issue, according to reports from Moscow.]

Cuba's Prensa Latina, however, is generally considered a government instrument. The commentary, which appeared unannounced on the local news agency wire but was not printed in Cuban newspapers, was signed by a leading agency editorialist.

"Maybe [the United States] is afraid that the two or three thousand Soviet soldiers that . . . Church says are in Cuba can invade and conquer the United States, turning that great country into a "second free territory in America," the commentator wrote.

Cuba often describes itself as the "first free territory in America."

The commentary at no time denies the troop presence, but rather refers to the "supposed presence of Soviet soldiers."

"It is frankly obvious" the commentary said, "that behind the North American accusations lies a maneuver directed not only against Cuba but against the movement of nonaligned countries now celebrating its sixth summit here."

The summit's celebration here in Cuba "cannot be a very agreeable drink for the imperialist palate," it went on. The U.S. government "has done everything possible" to make the summit a failure.

President Fidel Castro, in his speech opening the summit Monday, accused the United States of trying to sabotage the conference and of lobbying movement members to turn them against Cuba.

"This whole scandal is no more than yet another maneuver by the U.S. government, whose foreign policy recently has been characterized by a series of blind acts, and by an erratic and vacillating path that . . . shows little common sense," the commentary said.

"The senators can sleep peacefully," it said. "The Soviet soldiers, who liberated many people from the claws of Nazi fascism, who contributed so much to the fall of Hitler . . . could never be a threat to anyone.

"Cubans can defend themselves . . . they are the descendants of the men . . . of the Bay of Pigs and soldiers trained under the comradely assistance of their Soviet brothers in tactics and modern military strategy and in the use of defensive arms."

The U.S. attack, the commentary concluded, "is a product of the delirious mentality of some Yankee congressmen who see 'pirates on the horizon,' -- who knows for what dark designs?"