WASHINGTON - The Supreme Court has declined to decide whether Exxon Mobil Corp. must pay interest to victims of the nation's worst oil spill that would roughly double the $507 million judgment the high court approved in June.

In a brief order today, the court said the 9th U.S. Circuit Court of Appeals, based in San Francisco, should decide the matter of interest arising from the 1989 Exxon Valdez disaster.

The issue is whether interest has been accruing since 1994, when a federal jury first awarded punitive damages for the supertanker's spill of 11 million gallons of crude oil into Alaska's Prince William Sound.

The fishermen and other victims of the spill said that if interest is not owed from that date, the value of the award when adjusted for inflation would be cut in half. Exxon has argued that no interest is due.

The jury awarded $5 billion, but that was cut in half by the 9th Circuit. The Supreme Court, by a 5-3 vote, reduced the total to $507 million.