Hundreds of Nicaraguan troops on Wednesday headed to the Indio Maiz Biological Reserve, on the border with Costa Rica, to work to suppress a wildfire that continues to rage uncontrolled.
The troops left the town of El Castillo - some 365 kilometers (230 miles) south of the capital - in small boats known as "pangas" at 8:30 am and are expected to reach area of the blaze by 5 pm.
At least 1,200 people - mostly military personnel - are participating in the effort to battle the wildfire using 10 speedboats and several helicopters, including a Mexican air force MI-17 designed specifically for emergencies of this kind.
The army prohibited reporters and volunteers not related to the central government from entering the area for "security purposes," but residents en route to a neighboring town were allowed to do so unmolested.
The blaze started eight days ago and remains uncontrolled due to the large number of "yolillales" - a kind of palm tree with a high oil content - in the area and the fact that the zone can only be accessed by river or air.
Indio Maiz, an expanse of lowland rainforest some 2,093 square kilometers (about 810 square miles) in size, is part of the Mesoamerican Biological Corridor, home to thousands of bird varieties, including hundreds on the endangered species list.
Authorities suspect the fire resulted from arson.