New US expulsions show spy concerns. Washington's retaliatory ousters cast pall over relations between superpowers

The escalating superpower confrontation over embassy ``spies'' threatens to undercut what seemed to be a thaw in US-Soviet relations. The latest in a tit-for-tat series came yesterday when the United States advised the Soviet government that 55 diplomats are being expelled from the Soviet Embassy in Washington and consulate in San Francisco.

This occurs just as Moscow has been allowing prominent dissidents to leave and just as new moves in arms control were at least being seriously discussed. Whether or not the latest in ``embassy wars'' undercuts the more positive developments in relations remains to be seen. But Washington is making it very clear that combating espionage and tightening US security are paramount.

State Department spokesman Charles Redman said five of the expulsions were in response to a Soviet decision to expel five American diplomats from the Soviet Union. The 50 other expulsions, he said, were carried out in order to ensure ``parity'' between the size of the Soviet and American diplomatic missions in both countries.

The distinction is an important one. The Soviets can replace the five diplomats expelled in retaliation for the Kremlin's action; they cannot replace the 50 others. Mr. Redman said ``all 55'' were engaged in ``impermissible activities'' -- a diplomatic euphemism for spying.

According to State Department officials, the latest expulsions reflect a determination that Soviet diplomatic missions in the US shall no longer be used as covers for extensive espionage operations.

But will the Soviets retaliate? Redman says they have no reason to, claiming that Soviet diplomats had been told well in advance that the size of the Soviet diplomatic missions in this country would be reduced if Americans were unjustly expelled from Moscow.

The five Americans expelled last Sunday were accused of spying. But the move was widely seen as a retaliation for the earlier expulsion of 25 Soviet diplomats from the Soviet mission to the United Nations.

``The Soviets,'' Redman said, ``were aware of what was going to happen if they retaliated in Moscow.'' But, he says, the matter should now be laid to rest. ``We've reduced our respective diplomatic mission to parity, and therefore no retaliation would be justified.'' He also stressed that the US does not want the move to upset ongoing discussions over nuclear weapons reductions.

``The problem of espionage is a big problem, an important problem, but it's a separate one. . . . We remain committed to pursuing the dialogue,'' he said.

Whether the Soviets will share that view is problematical. Before the announcement of the expulsions, Soviet Foreign Ministry spokesman Gennady Gerasimov said in Moscow that if the US wants to engage in ``tit-for-tat'' expulsions, then the Soviet Union would take up the challenge. The Soviet news agency Tass said in Washington that the US action was ``the next step aimed at worsening Soviet-American relations.''

The imbalance between the US diplomatic mission in Moscow and the Soviet diplomatic contingencies in Washington, San Francisco, and New York has been a matter of continuing concern, not only for the State Department but for Congress as well. The Soviet Union now has 301 diplomats in the US and -- until the latest move -- had US authorization to fill another 19 vacancies, for a total of 320. The US, however, had only 251 diplomats in the Soviet Union.

The imbalance resulted, in part, from different philosophies of embassy staffing. Until last year, some 200 Soviet employees worked at the American Embassy in Moscow, performing a wide range of duties, from grounds cleanup to food preparation to translation duties. US diplomats argue that the use of local employees saves money, and promotes contact between cloistered American diplomats and the local populace.

The Soviet employees at the US Embassy, however, are employed by the Agency for the Service of the Diplomatic Corps, known by its Russian acronymn, UPDK. It is widely believed to be directly subservient to the Soviet secret police, the KGB.

By contrast, the Soviet diplomatic missions in New York and San Francisco do not employ Americans -- except for occasional translation chores. The people who pour the drinks at embassy receptions and dust the chandeliers are all Soviet citizens.

The US, under pressure from Congress, has been adopting a similar policy, and has been systematically reducing the number of Soviet employees in its Moscow Embassy and replacing them with Americans.

That effort will doubtless be set back with the new, unilateral American action to place a cap on the size of the missions that is exactly equivalent to the present size of the US missions in the Soviet Union.

Redman says, however, that the US is prepared to live within the strictures imposed by the new limit.

The move comes as concerns about the security of America's secrets are coming into sharp focus. A Senate committee report charges that cost overruns and construction delays at the new American Embassy in Moscow have soared. There are also reports that the building may be riddled with eavesdropping devices.