HOUSTON -- Iranian crude oil, banned from U.S. shores since 1987, could resume flowing soon now that federal authorities have eased import restrictions.

But oil industry officials said they doubt U.S. ports are about to be jammed with tankers bound from the Persian Gulf nation.

They said the changes in the law are limited, domestic refiners are chock-full of the type of high-sulfur "sour" crude Iran produces and demand is light. The crude is used to make industrial fuels and heating oil.

"There's not a lot of buying interest right now for any crudes -- sweet or sour -- because refiners are cutting back on runs," said James Ritterbusch, an analyst with PaineWebber Inc. in Chicago.

A handful of oil companies were advised last month that Washington was easing a 1987 ban on trade with Iran to give Tehran money to pay for cases before the Iran-U.S. Claims Tribunal in The Hague. The tribunal was set up to adjudicate billions of dollars in claims by both sides after the 1979-80 Iran hostage crisis.

Officially, the United States imposed the import ban because Iran refused to comply with a U.N.-sanctioned cease-fire in the Iran-Iraq war. But diplomats at the time also said the move was designed to choke Iran economically.

Before the ban, Iran is estimated to have shipped about 300,000 barrels a day to the United States. The bulk went to refiners in the U.S. Virgin Islands.

A spokeswoman with the Office of Foreign Assets Control, a division of the Treasury Department, said details governing which oil companies can apply for permission to import Iranian crude will be issued this week. She said she did not know if the policy change would apply to all oil companies or just those that had claims against Iran.

But oil industry sources said the restrictions would be eased only in limited cases and may cover only companies with outstanding claims.

Industry sources termed it unlikely that former U.S. customers would rush to reestablish ties with Iran unless it offers sizable discounts.