Brussels — The Kremlin may be scraping the limits of its aid to non-European client states, such as Cuba and Vietnam. From 1970 to 1980 the Soviet Union spent some $6 billion to $7 billion in economic and military aid on its non-European client states around the world. These figures come from a recently disclosed report from the North Atlantic Treaty Organization.
In contrast with a recent United States Central Intelligence Agency study of the expanding Soviet economy, this study projects increasing internal pressure limiting such foreign assistance.
The NATO study concludes that ''Soviet economic aid to client states - unlike arms, in which the Soviet economy is specialized - may be closer than ever to its limit, particularly in view of the growing, competing economic requirements of Eastern Europe.''
Therefore, the study continues, ''The relationship between the Soviet Union and its noncommunist developing clients (and even its communist clients) could come under increasing pressure as the need for economic, rather than military, assistance grows, particularly as a result of postwar reconstruction in African countries.''
While the aid amounts to just 0.02 percent of the estimated Soviet gross national product (the West's percentage is generally higher), the economic and financial burden is not negligible for the Soviet economy. Among the reasons Moscow may be reaching the limits of its aid:
* The cost of developing large, underdeveloped areas within Soviet borders.
* Unfilled domestic needs that limit public support for foreign aid.
* The fact that such aid drains much-needed hard currency from Soviet coffers.
Nevertheless, the study states that ''the Soviet leadership's willingness in the past to impose sacrifices in order to incur perceived political gains vis-a-vis the West should never be ignored.'' The survey notes that economic aid channeled by the Soviet Union and other Warsaw Pact countries in 1980 amounted to just under $5 billion, while the amount of economic aid from industrialized Western countries hit $29 billion.
This survey also points out that Cuba was by far the largest beneficiary of Soviet aid, accounting for about half of the total. The next largest recipient was Vietnam, followed by Mongolia, Ethiopia, Angola, Afghanistan, Mozambique, South Yemen, Kampuchea, Laos, and North Korea.
The total of $6.2 billion in Soviet aid in 1980 was slightly below the $7 billion registered in 1979. However, in 1980 military aid amounted to only $1.2 billion while military aid was more than $2 billion in 1979, when arms deliveries to Vietnam surged to $1.5 billion in connection with its invasion of Kampuchea (Cambodia).
In addition to aid grants, price subsidies, development projects, and other forms of assistance, the report notes that the Soviet Union is sometimes a country's largest or virtually sole trading partner. It adds that some countries , such as Mongolia, are dependent on the Soviet Union for their economic existence. For purposes of the study, recipient states were classified in two ways:
* Developing countries with consolidated Marxist-Leninist regimes - Cuba, Mongolia, Vietnam, Kampuchea, Laos, and North Korea.
* Developing countries with Marxist-Leninist-oriented regimes that have not fully consolidated their power - Angola, Ethiopia, Mozambique, Afghanistan, and South Yemen.
The Soviet Union is said by the study to spend generously on the first group and less on the second, which could grow to include Nicaragua and Grenada.
The study reported that Soviet aid accounted for about 25 percent of Cuba's gross domestic product. Mongolia is a state that is virtually dependent on Soviet aid, estimated at between $445 million and $735 million in 1980. Growth in the amount of aid to Laos, Kampuchea, and especially Vietnam was reported in recent years. The other developing countries with less stable Marxist regimes, such as Afghanistan and Ethiopia, receive a greater proportion of their Soviet aid in the form of military supplies.
Except for Afghanistan, none is receiving significant amounts of Soviet economic aid. Some have also been turning to Western sources, although the Soviet aid is regarded as critical.
The survey also confirms reports that the Soviet Union, despite its aid, ''is draining resources from Afghanistan,'' including all its natural gas and other minerals. On balance, the survey characterizes the Afghanistan venture as a short-term economic loss for the Soviet Union, but adds that political and strategic considerations, and perhaps longer-term economic advantage, are paramount.