MOSCOW, July 20 (RIA Novosti) - Talks between Honduras' interim government and ousted President Manuel Zelaya have broken down, with Zelaya pledging to return home next weekend.

The head of the interim government's delegation said on Sunday that Costa Rica's compromise proposal that Zelaya return as leader of a national unity government was "absolutely unacceptable".

Zelaya's representatives retorted that they would no longer participate in talks with interim leader Roberto Micheletti's delegation.

Zelaya later told reporters in the Nicaragua capital of Managua that he would return home "next weekend." An attempt by Zelaya to return to Honduras earlier in the month was blocked by coup supporters, with crowds forcing his plane to fly on to Nicaragua.

Costa Rican President Oscar Arias, who is leading mediation efforts, has asked both sides for another 72 hours to try to rescue the situation, amid fears that violence could break out in the Central American state.

The Honduran military arrested Zelaya on June 28, the day polls were due to open for a referendum on the extension of his non-renewable, four-year term of office, and flew him to Costa Rica.

The country's Supreme Court had ruled the referendum illegal. The president was arrested at his residence and transported aboard a military plane to Costa Rica in what was Central America's first coup since the end of the Cold War.

World leaders have condemned the coup, with UN Secretary General Ban Ki-moon urging "the reinstatement of the democratically elected representatives of the country."