Costa Rica  sent a team to a disputed border zone Tuesday to carry out environmental  tests, prompting an angry response from Nicaragua as an international panel  was considering the case.

Costa Rica said the mission, including 13 of its officials and  three experts from the Ramsar Convention on wetlands, were seeking to assess  environmental damage in the area from Nicaraguan dredging which triggered the  border dispute last year.

Managua called the action a "provocation" that violated the UN's  International Court of Justice order to refrain from deployments during the  court's deliberations in the case.

Military intervention

Heading the mission which arrived by helicopter, Costa Rican  Foreign Minister Roverssi said his country was prepared for possible  interference by the Nicaraguan military.

"We have planned for an evacuation program if it is needed,"  Roverssi told reporters at Barra del Colorado, a tiny river island on the  Caribbean coast accessible only by boats and aircraft.

But the Nicaraguan army chief, General Julio Cesar Aviles, said the  move appeared to be aimed at gaining territory.

Aviles said that Nicaragua has not increased military deployment,  but had ordered troops on the border to "take precautions due to the constant  provocation of Costa Rica."

Nicaragua's deputy environment minister said around 100 members of  the ruling Sandinista party would be demonstrating and waving Nicaraguan flags  around the border "to show them where Nicaragua is."

ICJ steps in

On March 8 in The Hague, the UN court ordered both countries to  refrain from deploying or maintaining any military or civilian personnel in  the disputed area.

"Each party shall refrain from any action which might aggravate or  extend the dispute before the court or make it more difficult to resolve,"  said judge president Hisashi Owada of the International Court of Justice.

But the court also indicated it wold be permissible for Costa Rica  to send environmental officials to the area to avoid "irreparable" harm to the  wetlands, as long as Nicaragua was notified in advance. 

Costa Rica has claimed Nicaraguan troops were illegally occupying  an area of three square kilometers (1.16 square miles) in its northeast in a  move that "endangers stability and peace between two brother countries."

It also sought a stop to all canal construction activity, which it  claimed would impede the flow of water to its own Colorado River.

Nicaragua had asked the court to dismiss the case, which it said  concerned "a swamp of three square kilometers."