Moscow — As Arab frustration mounts over United States policy in the Middle East, the Soviet Union is seeking to spread its own influence in the troubled region. But despite a number of visible successes, the Russians seem to lack any clear strategy for capitalizing on America's slippage in the Arab world.
That is the composite view of a number of diplomatic analysts here in Moscow, as Syrian President Hafez Assad heads home after a three-day visit here.
He is the latest in a string of Arab visitors, but he won't be the last. Iraqi Foreign Minister Tareq Aziz arrived Thursday. King Hussein is due for a visit once the Soviets fix a date. And there are widespread, though unconfirmed, reports that Palestine Liberation Organization leader Yasser Arafat is also planning a visit sometime later this year.
Earlier this month, the Soviet Union signed a friendship accord with North Yemen, and before that a high-level delegation from South Yemen visited. Those events, together with a major arms sale to Kuwait and renewed diplomatic relations with Egypt, amount to greatly heightened Soviet involvement in the region.
But the Assad visit spotlights many of the pratfalls awaiting a superpower that ventures into the Middle East cauldron.
Mr. Assad, Moscow's main ally in the region, apparently came seeking expanded economic aid plus a guarantee of continued military support for its presence in Lebanon - a presence made necessary, the Syrians say, because of the Israeli presence in the country.
But one analyst characterized Assad's reception here as ''lukewarm, bordering on cool.'' The two sides, however, did reveal in a joint communique that Soviet President Konstantin Chernenko has accepted an invitation to visit Syria. More military aid was promised, Syria said.
Earlier, however, analysts in Moscow noted that the Kremlin did not publish speeches given by the two leaders during a working lunch at the Kremlin. That, they speculate, may be a sign that the session did not go well.
And in a Tass account of a meeting between Mr. Chernenko and Assad, diplomats noted that the Kremlin pointedly pledged to give ''all-round assistance'' to Syria and ''the other Arab peoples.''
That, according to Western analysts, suggests that while Syria is still Moscow's main ally in the region, the Kremlin does not want to tie itself too closely to Assad, Western analysts say.
The reasons are numerous, but chief among them is probably the continuing bitter dispute between Assad and another of Moscow's allies, PLO leader Arafat. The Kremlin is keen to see the rift sealed, but pressure on both sides has apparently failed.
For that reason, analysts speculate, Soviet guarantees of assistance have been deliberately vague.
Beyond that, the Soviets are also pushing their own formulation for Middle East peace - an international conference to hammer out a comprehensive settlement for the region's problems. The Russians, of course, envisage a key role for themselves in brokering such a conference.