THE HAGUE, Netherlands (AP) _ Few nations are as suspicious of each other as the United States and Iran. But in an unmarked building on the outskirts of this Dutch city, the two nations quietly meet _ and hundreds of millions of dollars change hands.

For almost 15 years, American and Iranian delegates have literally held court in an inconspicuous former hotel, their success as great as the secrecy of their deliberations.

The three judges from the United States, three from Iran and three from other countries arbitrate financial claims between Washington and Tehran arising from the 1979 Iranian revolution.

Their work has short-circuited disputes that left unattended might have made relations between the two nations even more tense.

The forum is the Iran-United States Claims Tribunal. Its closed sessions resemble U.S. civil court proceedings, with witnesses, examination, argument and rebuttal.

But there is no ceremony and little formality, no judicial robes, no oaths on the Bible or the Koran.

Indeed, there is a conscious effort to keep ideology outside the three-story, brick building, which sits behind a gated fence and whose remote-control doors are guarded by a Dutch security firm.

Neither American nor Iranian flags appear inside or out, and the rare political outburst is quickly quelled by judges.

``This is not Panmunjom,'' said a tribunal source, referring to the truce village in the demilitarized zone between North and South Korea. ``This is a legal proceeding, not a diplomatic one.''

Legal agents from the two governments and private lawyers sit along opposite wings of U-shaped wooden tables in two hearing rooms, arguing their cases in English and Farsi before a three-judge panel at the end. Simultaneous interpretation drones through their earphones.

The tribunal has three such panels, each with one Iranian, one American and one third-country neutral judge.

Despite the backdrop of political bitterness, the daily hearings in the marble and wood-paneled chambers have resolved almost 4,000 cases arising from expropriations, the freezing of assets and broken contracts.

That has meant about $2.1 billion for American claimants and about $900 million to Iranians, with billions more in interest.

But there is another, more intangible benefit _ direct access between governments when needed, such as that involved in settling Iranian claims from a U.S. warship shooting down an Iranian jetliner.

In late February, Tehran accepted Washington's proposal to pay $61.8 million in compensation to survivors of Iranians killed when the cruiser USS Vincennes shot down an Iran Air A-300 Airbus over the Persian Gulf on July 3, 1988. Iran previously had balked at the U.S. demand to pay the survivors directly rather than funnel the money through the Tehran government.

As part of the negotiations that led to the settlement, Washington agreed to pay an additional $70 million to cover Iranian bank claims against the United States as well as tribunal upkeep.

``It was a way out of an impasse,'' said the tribunal source, who like others associated with the tribunal spoke on condition of anonymity to avoid upsetting the delicate balance. ``You do this for me and I'll do this for you.''

The Airbus case had been before the high-visibility International Court of Justice in The Hague for years until both sides decided to settle low-key via the tribunal.

``The tribunal has been there during the worse periods of Iran-United States relations,'' said Terry Gill, an international law professor at Utrecht University. ``It's the only way they could get around the problems resulting from the change of power in Iran.''

The tribunal was spawned by the American Embassy hostage crisis in Tehran. The 1980 accord that freed American hostages held by Iranian militants for 444 days also set up the tribunal.

At the court, American judges view their Iranian counterparts as direct advocates of their government, while the Iranians tend to scratch their heads in bewilderment when the U.S. judges vote against American parties, former officials say.

But rulings avoid the political, and arbitration hearings proceed with civility and courtesy.

It wasn't always so.

In September 1984, two Iranian judges thought neutral judge Nils Mangard of Sweden was not neutral enough and assaulted him, forcing a three-month suspension in the tribunal's work.

Things have calmed down into routine since, although the Iranians and Americans still do not mingle socially.

The biggest hurdles remaining are the politically loaded cases: U.S. citizens of Iranian birth with claims against Iran, Iran's claims on the property of former Shah Mohammed Reza Pahlavi in the United States and the sale of U.S. military equipment.

After the shah was deposed, the United States froze delivery of weapons purchases, much of them already paid for. Iran contends Washington owes it up to $12 billion for the broken contracts. U.S. officials say that is highly inflated.

How long will the tribunal take to plow through its remaining docket?

``At the rate things are going, I thought I was going to retire at my desk,'' said a tribunal source. ``Now I think I'm going to die at my desk.''