Disband Now, 5 Latin Leaders Urge Contras : Central America: Two-day summit ends. The presidents set a deadline for cutting their armies.

In a bid to intensify pressure on the U.S.-backed Contras, five Central American presidents Tuesday urged the Nicaraguan rebels to disband immediately and give up their guns to U.N. peacekeeping forces.

Ending a two-day summit at this Pacific Ocean resort, the leaders also invited Panama for the first time to join economic and political talks. A U.S. invasion last year ousted Panamanian strongman Manuel A. Noriega.

The meeting was the latest in a three-year-old regional peace process that earned its author, Costa Rican President Oscar Arias Sanchez, a Nobel Prize and gave birth to a plan that has been used to gradually weaken the Contras while fostering democratic reform in Nicaragua and elsewhere.

“As soon as the Contras are demobilized and disarmed, we can close the chapter on war,” Nicaraguan President Daniel Ortega said.

The Montelimar summit is the last for both Ortega and Arias, the 1987 Nobel Peace Prize laureate. In elections Feb. 25, Ortega and his leftist Sandinistas lost to opposition publisher Violeta Barrios de Chamorro. Arias was prevented by law from running for reelection.

In a 17-point document, the presidents of Nicaragua, Costa Rica, El Salvador, Honduras and Guatemala told the Contras to lay down their weapons by April 25, the date Chamorro is scheduled to be inaugurated. An April 20 deadline was established in an agreement signed by the Contras on March 23 but has been interpreted to apply only to rebels encamped in Honduras. In recent weeks, thousands of fighters have moved from Honduras into Nicaragua in an apparent effort to avoid the deadline.

Now, the presidents are telling the Contras, inside and outside Nicaragua, that they must disband by April 25. The document also urges the rebels to hand their weapons over to U.N. forces, who will destroy them “on sight.”

In practical terms, the Contras are not likely to heed the presidents’ agreement. The rebels have ignored every deadline set for them to demobilize.

But the document represents an important show of political support for Ortega, who, under terms of the regional peace plan held--and lost--free and fair presidential elections.

Diplomats said the presidents were willing to reward Ortega and easily reached agreement on joining in the Sandinista government’s demand that the Contras be dismantled as a fighting force.

In the accord, the presidents also asked that money allocated to resettle the Contras be channeled through a verification commission created by the Organization of American States. The U.S. House of Representatives on Tuesday passed a $300-million aid package for Nicaragua, including $30 million for repatriation of Contra fighters and their families. The Senate has yet to act on the bill.

The Central American leaders asked that the money be given only to former members of the Contra forces who have disarmed. It was not clear how it would be determined that a Contra fighter had turned in all of his weapons.

Despite clear difficulties in enforcing the Montelimar accord, Nicaraguan negotiators were pleased that many of their demands had been met. They hailed the agreement as an important step in putting pressure on the Contras to disband, something that the Sandinistas, Chamorro and even the White House are urging.

The accord also praised a new effort at negotiations between the right-wing government of El Salvador’s President Alfredo Cristiani and Marxist-led rebels of the Farabundo Marti National Liberation Front. Representatives of the two sides are scheduled to announce a new timetable for peace talks today in Geneva, under auspices of the United Nations.

Similarly, the presidents hailed the start of talks between Guatemala’s National Reconciliation Commission, which includes representatives of the Roman Catholic Church and the government of President Vinicio Cerezo Arevalo, and the Guatemalan National Revolutionary Union, a leftist guerrilla group.

Some presidents said that with the Nicaraguan war apparently subsiding, the focus of future meetings is likely to shift to the region’s overwhelming economic troubles, crises marked by stubborn poverty and staggering foreign debts.

“Our goal is that there be total peace in Central America, so that we can move to strengthen our economies,” Honduran President Rafael L. Callejas said.

The tone of the two-day summit was relaxed and largely free of the bitter divisiveness that has characterized some past meetings, diplomats said.

On Tuesday, however, the five presidents were walking down a paved hillside to the thatched-roof gazebo where the agreement was announced. Suddenly, an earthquake started shaking the resort. One of the presidents grabbed his bodyguards while journalists ran toward the ocean.

No one was injured, and there was little damage. The U.S. Geological Survey in Golden, Colo., said the earthquake had a magnitude of 6.5 and was centered off the coast of Costa Rica.