The foreign ministry said Monday that no Nicaraguan troops can be seen at the former camp on Costa Rican soil.
Officials think that the Nicaraguan soldiers may have pulled out, but a dredge still is hard at work trying to open a new mouth to the Río San Juan. More dredges are expected to join the work, according to news reports from Nicaragua.
The location is on the Isla Los Portillos, the land that Nicaraguan troops invaded in October. Costa Rican security officials have declined to send heavily armed police into the area.
They said they suspected some kind of trap.
Pulling out the troops was exactly what the Organization of American States demanded when Costa Rica brought the case of the invasion to the hemispheric body. The organization stopped short of taking sides and said that both countries should step down. Costa Rica has put significant forces in the border area.
The foreign ministry also said that in a presentation to the International Court of Justice in the Hague, the Nicaraguan ambassador, Carlos Argüello Gómez, said there were no troops in that area. The foreign ministry said that Nicaragua was litigating in bad faith.
Costa Rica refuted this statement a few days later when it presented photographic proof to the court, the ministry said.
The Ministerio de Relaciones Exteriores y Culto also said that the air photos clearly show environmental damage in the location. The ministry released photos.
Costa Rican officials still are counting on an order from the international court, which has jurisdiction over the boundary between the two countries.
Officials have asked the court to issue what amounts to a stop-work order, a preliminary decision is expected this month.
The purpose of the dredging is to open a new mouth to the river so that boats can avoid the meandering and silted-up beginnings to the river. Nicaragua has announced major improvements in the area, including a refurbished airport.
The withdrawal of Nicaraguan troops might not be ominous. The area is marsh and beach with lagoons that produce hordes of mosquitoes. Costa Rica has made no attempt to challenge the occupation. The Nicaraguans dug foxholes around their headquarters. These appear to be empty, too, based on the air photos.