SAN JOSE, Costa Rica-- Costa Rican officials are preparing to go before the Organization of American States on Wednesday to seek support in a dispute with Nicaragua over the river dividing the two countries -- continuing a lengthy feud between the Central American neighbors.

Costa Rican officials asked for the meeting over allegations that Nicaraguan troops have intruded into Costa Rican territory and that Nicaraguan dredging of the river caused environmental damage. Nicaragua denies both allegations.

The country will try to avoid a confrontation that would aggravate the situation. Costa Rica sent more police to the area on Monday.

The river has been a source of disputes for nearly two centuries. Last year, the United Nations' highest court set travel rules for the San Juan, affirming freedom for Costa Rican boats to navigate the waterway while upholding Nicaragua's right to regulate traffic.

The latest argument stems from a Nicaraguan project to dredge the river. Costa Rica objected to the plan when it was announced last year.

news conference Tuesday that he hopes the OAS will take swift action and send a commission to the conflict area to assess the situation.

Nicaraguan Deputy Foreign Minister Valdrak Jaentschke said his country is working on a response for the OAS meeting.

Costa Rica said that after receiving reports of Nicaraguan soldiers on its soil, it initially sent some 70 police reinforcements to the border area Oct. 22, a day after it formally complained to Nicaragua's ambassador about the dredging.

Nicaragua's army chief of staff, Gen. Julio Aviles, said he has soldiers on the Nicaraguan side of the border as part of an anti-drug operation.

Aviles contended the allegation about troops crossing the border comes from a Nicaraguan drug-smuggling family living in Costa Rica that is trying to undermine Nicaragua's anti-drug fight.

"The army has always maintained a constant guard on the San Juan River in its fight against international drug trafficking and at no time has violated international norms and treaties, nor has it invaded foreign territory," Aviles said.