WASHINGTON (AP) - Attorney General Eric Holder has told Congress that the Justice Department is prepared to go to trial against companies involved in the Gulf oil spill if ongoing negotiations do not result in a settlement.

At a hearing before a House appropriations subcommittee, the attorney general vowed that the federal government will hold people accountable in both a civil trial in federal court in New Orleans, if necessary, and in a criminal investigation. Holder declined to elaborate on the discussions.

Under questioning by Republican Rep. Jo Bonner of Alabama, Holder agreed that the accident was the worst environmental disaster in U.S. history.

On Sunday, a judge called for a one-week delay in the start of the civil trial while negotiations continue. The trial had been scheduled to begin Monday.