DUBAI, United Arab Emirates — As the United States moves to further isolate what it regards as the outlaw regime in Iran, it is finding it difficult to recruit to the cause those countries seemingly most directly threatened, the oil-rich Arabian states on the Persian Gulf.

Out on what one Arab official calls "the front line" of potential confrontation with Tehran, the United States' allies in the Gulf War--Saudi Arabia, Kuwait, Bahrain, Qatar, Oman and the United Arab Emirates--are pursuing their own policies on Iran, and not always in step with Washington.

The Gulf states' stance follows the lack of enthusiasm exhibited by most European nations and Japan for the Clinton Administration's trade ban on Iran.

The Administration is responding with a campaign of diplomatic persuasion and by emphasizing the continued close military cooperation among the Gulf states, the United States, Britain and France, according to diplomats and analysts in the region.

Few officials here dispute Iran's growing military strength and its potential for mischief-making in the Gulf.

Shipping sources in this trading capital, for example, cite a handful of hijackings of civilian ships by speedboats believed to be operated by the Iranian Revolutionary Guard.

Boat crews have boarded ships in international shipping lanes in the Gulf, forced them to divert to Iranian waters and then demanded payments of tens of thousands of dollars to release the vessels.

An official of the U.S. Navy in the region confirmed that one of its ships witnessed such a boarding of a seagoing tug and apparently frightened off the would-be hijackers.

Nor is there much doubt about Iran's long-term ambitions of political, economic and military dominance in the region.

If Iran can establish itself as what one official called "the 500-pound gorilla in the Gulf," it can influence everything from resolution of numerous border disputes to oil production and pricing.

Nonetheless, there is some skepticism that the Administration's policy of trade barriers and economic isolation is the best way to influence the Tehran government.

"Squeezing Iran, as well as Iraq, with their huge populations . . . will just mean . . . more poverty, and that means more political instability. The price that might have to be paid will be paid directly by us," said Kuwaiti economic consultant Jasem Sadoun in a typical analysis.

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