The presidents of five Central American nations began arriving Sunday for two-day summit aimed at reviving the stalled peace process in the region.

The leaders planned to meet Monday and Tuesday in the exclusive Pacific resort of Playa Costa del Sol, 24 miles southeast of San Salvador, to review progress on a regional peace plan signed Aug. 7, 1987, in Guatemala City.Nicaraguan President Daniel Ortega arrived at El Salvador International Airport at 6:30 p.m. aboard a presidential jet. It was Ortega's first official trip to El Salvador, and his visit was criticized by right-wing groups opposed to his Marxist Sandinista government.

"We hope to work toward agreement on concrete political issues, and verification of regional security during the meeting," Ortega told reporters as he stepped off the plane. "I am glad to be in El Salvador and I salute all the Salvadoran people on this occasion."

A Nicaraguan technical team arrived at the Tesoro Beach Hotel, site of the summit, two days earlier to inspect security arrangements.

Costa Rican President Oscar Arias was scheduled arrive an hour after Ortega on a Panamanian airline flight. It was reported Arias would hold a private meeting with Salvadoran President Jose Napoleon Duarte, but the report could not be confirmed.

The exact arrival time of Honduran President Jose Azcona Hoyo was not known, and Guatemalan President Vinicio Cerezo was scheduled to arrive Monday morning in time for the 10 a.m. opening ceremony.

Security around the posh resort was extremely tight in advance of the summit, as some 300 national police officers patrolled the area, backed by troops.

In the capital, several bombs blasts were heard throughout the evening. The groups responsible for the bombings were not known, but Marxist rebels belonging to the Farabundo Marti National Liberation Front have declared a unilateral 48-hour truce beginning at 12:01 Monday.

The August 1987 peace plan was the brainchild of Arias, who won the Nobel Peace Prize that year for his efforts.