High-ranking government and rebel delegations agreed on a 10-day suspension of direct peace talks after a fourth day of negotiations failed to produce a definitive cease-fire pact.

Also Monday, President Daniel Ortega warned that Sandinista troops would continue fighting the U.S.-backed rebel forces if rebel negotiators bowed to pressure from their top military commander not to sign an accord.A joint communique issued at the end of Monday's talks said the government and the Contras, as the reb-els are known, would next meet in Managua April 28-30 to continue negotiations to end their 61/2-year-old civil war.

The statement described talks between Sandinista officials and leaders of the Contras' Nicaraguan Resistance organization as "frank and cordial" and said the two sides had entered into "permanent session" to reach an accord.

Contra leader Pedro Joaquin Chamorro told reporters that government and rebel officials had agreed "that at any moment we can renew the negotiations to give continuity to this process."

"We are certain the negotiations will end in success," said Nicaraguan Defense Minister Humberto Ortega, who headed the government's negotiating team.

President Ortega, the defense minister's brother, charged that Col. Enrique Bermudez, the Contra military commander, and the United States were pressuring rebel negotiators to avoid a cease-fire agreement.

According to Ortega, Bermudez threatened the Resistance directorate saying rebel military forces "would liquidate them" if they signed an agreement with the government.

"If this happens, it would leave us no other road but to achieve a total victory in the military field," Ortega told thousands of government supporters gathered in Managua's Plaza de la Revolucion on Monday evening.

Alfredo Cesar and Adolfo Calero, leaders of the Resistance directorate, denied Ortega's claim. The directorate's six members arrived in Managua on Friday for the first time since the civil war began in November 1981. They left the country Monday evening.

Officials from both sides declined to provide details on the latest round of talks. Humberto Ortega said they were "an advance and not a failure," while Calero, the highest-ranking Resistance official, told reporters that both sides were "on the road to an understanding."

Negotiations reportedly stalled over the issue of when the Sandinistas would introduce democratic reforms in Nicaragua. Arriving in Miami on Monday night, Calero said that would be the top issue when talks resume.

The Sandinistas insist the rebels sign a permanent truce immediately. They say Contra delegates would then be allowed to take part in a "national reconciliation dialogue" with leaders of Nicaragua's 14 legally recognized political parties.

Contra leaders demand the Sandinistas first carry out a series of democratic reforms, or at least pledge to do so, before they will sign a pact.

The two sides signed a provisional agreement on March 23 which provided for a temporary cease-fire while they negotiated a permanent truce. A 60-day cease-fire went into effect April 1.