WASHINGTON — Both sides in Honduras’ leadership crisis on Tuesday signaled willingness to forge a diplomatic solution to the deadlock over the fate of President Manuel Zelaya, who was ousted last month in a coup.

Zelaya and interim Honduran leader Roberto Micheletti agreed to accept Costa Rican President Oscar Arias, a Nobel Peace laureate, as an international mediator. Arias’ appointment was backed by the United States and announced by Secretary of State Hillary Clinton after she met privately with Zelaya at the State Department.

Arias will conduct the mediation in Costa Rica, where Zelaya intends to travel from Washington, and Clinton said she expected the process to begin soon.

Zelaya said he was pleased with Arias’ appointment. “I have accepted Dr. Arias’ mediation,” he told reporters after seeing Clinton. He added that the step showed “the international community is still supporting democracy in Honduras.”

Meanwhile, in Honduras, Micheletti, who had vowed not to negotiate until “things return to normal,” appeared to open some space for a settlement to the crisis that began June 28 when Zelaya was detained by the military and forced into exile.

Arias “is a man with a lot of credibility in the world,” Micheletti said. “We are open to dialogue. We want to be heard.”

While Micheletti said he would send a delegation soon to Costa Rica — a reversal from past days — he also said the meeting “doesn’t mean that Zelaya will be allowed to return.” He later told a news conference that the dialogue with Arias should “start from the understanding that Zelaya’s return is not open to negotiation.”

In another hint of possible compromise, a Honduran Supreme Court official said Tuesday that political amnesty for Zelaya is possible.

Clinton would not discuss specifics of the mediation process, which she said would begin soon, but a senior U.S. official said one option being considered would be to forge a compromise under which Zelaya would be allowed to return and serve out his remaining six months in office with limited powers. Zelaya, in return, would pledge to drop his aspirations for a constitutional change that might allow him to run for another term.

Arias won the Nobel Peace Prize in 1987 for helping broker an end to Central America’s civil wars.