International mediators prepared to leave Managua and return home after an unsuccessful eight-week effort to avoid further bloodshed in Nicaragua and bring President Anastasio Somoza and his political opponents to agreement over the country's future.

Although Somoza accepted in principle Thursday a mediation proposal for a nationwide referendum on his presidency, the conditions he set for the vote and his refusal to promise to leave office immediately should he lose amounted to a refusal in the eyes of the opposition and, apparently, of the mediators.

The opposition accepted the proposal last Wednesday but with conditions that Somoza found unacceptable, including his departure from the country during the electoral period.

Somoza said in an interview with Associated Press that he had "given the most" in the mediation process, and if opposition leaders "don't like it they can go to hell."

He said that his decision to accept the plebiscite proposal was "motivated by peace and love for the Nicaraguan people."

Following the end of mediation by the United States, Guatemala and the Dominican Republic, the next step in international efforts to resolve the crisis will likely be a special consultative meeting of foreign ministers of the Organization of American States next week.