Soviet Premier Alexei Kosygin told a senior White House adviser at a Kremlin meeting Tuesday that Chinese Vice Premier Teng Hsiao-ping's anti-Soviet comments during his American visit amounted to "a declaration of war," senior Western diplomatic sources said today.

Kosygin devoted about 15 minutes of an hour-long Kremlin session with Frank Press, President Carter's science adviser, to Soviet concerns over Chinese-American relations and Teng's sharp attacks on Moscow.

The sources described Kosygin as measured and unemotional during that time, but firm in expressing Soviet disappointment and surprise that the administration had not publicly objected to Teng's remarks or found some way to officially dissociate itself from them.

Although senior U.S. officials have distanced themselves from Teng's remarks, the Soviets had earlier asked the White House to clarify its intentions more explicitly in the new Peking-Washington relationship.

The "declaration of war" remark is interpreted here as a figure of speech by Kosygin, meaning a probable intensification of the bitter propaganda war between the two Communist rivals, not armed conflict. Western sources here say there is no evidence of Soviet military buildup along its lengthy Chinese border.

Nevertheless, Kosygin's comments are being reported at a time when tension is mounting between China and the Soviet Union over the toppling of the Peking-backed Cambodian government by a Soviet-backed Vietnamese invasion last month. The Communist Party newspaper Pravda in its Saturday edition carries a major commentary charging China with troop buildups against Vietnam and military forays across the border in which Vietnamese are claimed to have been killed.

The article, signed by I. Alexandrov, which is commonly taken here as a pseudonym signifying Central Committee authorship, asserts:

"The bandit raids on Vietnam by the Chinese military prove once again that Peking regards Southeast Asia as a zone in which China's rule must be established in the long run, as a bridgehead for eventual possession of all Asia."

The Soviets' underlying view is that the Chinese have engineered rapprochement with the United States as a means of furthering their goals in Asia, and they suspect the Americans of tacitly approving.

Press was said to have repeated White House declarations that it plans an evenhanded policy toward Moscow and Peking, while Kosygin was said to have indicated that the Soviets think Washington should place its ties to Moscow above the new Chinese relationship.

Kosygin reportedly did not raise the question of final agreement on a strategic arms limitation pact now in the final stages of a prolonged negotiation, nor did he raise the general issue of detente between Moscow and Washington.

Saturday's Pravda article, transmitted by the Soviet news agency Tass in English tonight, does not make any specific or implied threats of retaliation against Peking despite the strong language.

The Soviets and Vietnamese recently signed a friendship and cooperation agreement calling for consultations in event of military attack by a third country.

An article published in the Moscow journal New Times yesterday cautioned China against "overstepping the forbidden line" in Vietnam

The original Vietnamese military blitzkrieg that drove Pol Pot from Pnom Penh and set up a Soietbacked "national front" government in Cambodia has sagged in the face of stiffening small-unit resistance. The conflict seems likely to become an open-ended affair involving both Chinese and Soviet military aid.