WASHINGTON -- A month before a U.S. deadline for Libya to hand over two suspects in the bombing of Pan Am Flight 103 in 1988, administration officialssay they are planning to seek tougher economic sanctions against the country. After months of diplomatic maneuvering, Col. Moammar Gadhafi has given no sign that he will accept a compromise from the United States and Britain on trial arrangements in the case.

President Clinton announced in December that the United States would push for tougher U.N. sanctions if Libya failed to hand over two intelligence agents for trial in the Netherlands by the end of February. But London and Washington have ruled out their imprisonment, if convicted, in a third country.

Speaking at a memorial service marking the 10th anniversary of the bombing, Clinton said the compromise offer to have the case heard by a Scottish court sitting in the Netherlands was a "take-it-or-leave-it offer." If the Libyans failed to hand over the suspects by the time the sanctions came up for review, the president said, the United States would ask the Security Council to approve tougher sanctions.

Despite the intervention of Secretary-General Kofi Annan, who met with Gadhafi in December, administration officials say the Libyans seem no closer to accepting the deal. Gadhafi seems to fear that if he hands over the agents, investigators will pursue evidence further up the Libyan chain of command, the officials said. The two suspects, Abdel Basset Ali Megrahi and Lamen Khalifa Fhimah, were indicted in 1991.

The White House is trying to determine how best to shape sanctions that would be more stringent, but not so onerous that they failed to gain passage in the Security Council.

Administration officials acknowledge that international fatigue with open-ended sanctions against Libya, coupled with pressure from Saudi Arabia and others, prompted the administration to propose the compromise. Saudi Arabia has regularly pushed the United States to find a way out of the impasse over Pan Am 103, and has intensified its lobbying on the matter, officials said.

Saudi Arabia has also tried to prod Gadhafi. President Nelson Mandela of South Africa, who is a longtime ally of Gadhafi, has also tried to mediate. Gadhafi has tried to use other nations as middlemen, offering money or the promise of aid in return.

The diplomatic pressure on the United States came as the Clinton administration concluded that the sanctions could not be kept in place indefinitely without an erosion of international support. U.S. officials say that some African countries were already allowing Libya to violate air travel sanctions in return for aid.

If Gadhafi does agree to the trial, the sanctions would not immediately end. Under U.N. resolutions, they would be suspended, but would not end permanently until the secretary-general certified that Libya had cooperated fully in the trial, and had severed all ties to terrorism.