Bangkok — As tension with China approaches its fifth month, Vietnam is receiving mixed signals from the Soviet Union and East bloc. Hanoi seems to have asked Moscow for more military aid. In some ways this would be a particularly appropriate time for the Vietnamese to do so, as the Soviet leader seems more favorably inclined toward Hanoi and less interested in friendship with Peking than his predecessor.
But the other East-bloc countries seem less keen on this approach; aid to Vietnam is, for them, at best a burden, while Chinese markets seem increasingly attractive.
Late last month Vietnam's Defense Minister, Van Tien Dung, made his second visit to Moscow in less than six weeks. The trip got minimal notice in the Vietnamese Communist Party newspaper, Nhan Dan, but Mr. Dung's Soviet intelocutors were far from insignificant. They included his counterpart, Marshal Dmitri Ustinov, who like Dung is a member of the Communist Party's Politburo; the Soviet armed forces chief of staff and deputy defense minister, Marshal Nikolai Ogarkov, who had visited Vietnam in February 1982; and another deputy defense minister, Marshal S. L. Sololov.
The meeting may well have been a follow-up to one Dung had in Moscow on May 16, at the beginning of an East European tour that Hanoi-based diplomats say was aimed at gathering diplomatic and military aid in the face of the continuing confrontation with China.
Dung's hosts on that occasion included Ustinov, Ogarkov, and the commanders of the Air Force, Marshal Pavel Kutakhov, and the Navy, Adm. Sergei Gorshkov.
The Navy and Air Force commanders would have had a particular interest in meeting Dung: By allowing the Soviets informal and apparently uninterrupted use of the major Vietnamese bases of Da Nang and Cam Ranh, Hanoi has given the Soviet Union an important military and political foothold in Southeast Asia.
The Vietnamese and the Soviets seem to have drawn even closer this year. Konstantin Chernenko seems less enthusiastic for detente with China than was Yuri Andropov.
Since April, the Soviets have usually cited alleged Chinese aggression against Vietnam for their lack of interest in improved relations with Peking. This was the reason they privately gave the Vietnamese for the last-minute cancellation of Deputy Premier Ivan Arkhipov's visit to Peking in May. And when Chernenko first criticized China by name, it was on June 11 during a meeting with the Vietnamese Communist Party general secretary, Le Duan.
In April, when the Sino-Vietnamese border was heating up, the Vietnamese held joint military exercises with the Soviets. Soviet marines landed on Vietnamese soil for the first time, Western analysts say. The Vietnamese say the exercise was routine.
Dung's May tour of Eastern Europe provided a graphic illustration of the extent and limitations of Vietnam's relationship with the East bloc.
The Soviet Union regularly grumbles about the inefficiency with which Vietnam uses its aid, currently estimated at about $1.2 billion annually, three-quarters of it economic. But Moscow is likely to keep the aid flowing at the same level for the foreseeable future. Its alliance with Vietnam has given it bargaining chips with China and the United States. And it has forced the countries of Southeast Asia, where its influence was formerly negligible, to treat it as a serious factor in regional security.
But the other countries of Eastern Europe receive little in return from Vietnam for their aid. They do not have global strategic ambitions, and Vietnam has little to offer them in merchandise or markets.
All of these countries, on the other hand, find the prospect of trade with China appealing. So, while Sino-Soviet and Sino-Vietnamese relations have deteriorated this year, other East European countries have maintained, and sometimes improved, their relations with Peking.
The most striking example of this is East Germany, whose aid program in Vietnam is second only to the Soviet Union. Dung canceled his visit to Germany at the last minute because, diplomatic sources say, the East Germans indicated they would not condemn Chinese aggression. The East Germans have become more openly critical of the way Vietnam spends, or wastes, their aid. And East German-Chinese ties - mainly economic but also political - have been improving.
When Hungary received Dung, it denounced China rather mildly, but promised further military aid. Czechoslovakia and Poland denounced China more vigorously, but were hazier on the subject of aid.
Two weeks after Dung left, another Communist leader visited Hungary, Czechoslovakia, and Poland: Chen Muhua, alternate member of China's Politburo and minister of foreign economic relations and trade.