There were no immediate reports of major damage Saturday, but thousands were evacuated. In Olanchito, near the northern coast, a creek overflowed and flooded a house but firefighters were able to rescue its 10 occupants.
The storm made landfall Friday on Nicaragua's Caribbean coast and quickly crossed into Honduras where it was pushing westward with winds of 40 mph (65 kph) toward Guatemala and Belize. It was expected to weaken into a tropical depression on Sunday.
But the US National Hurricane Center in Miami said Matthew could bring 6 to 10 inches (15 to 25 centimeters) of rain before it weakens, with the possibility of flash floods and mudslides. Some parts of Nicaragua already were coping with flooding due to earlier rains.
Nicaraguan authorities said they ordered the evacuation of 10,000 people.
In Honduras, authorities said they had evacuated 300 people from small communities in the Gracias a Dios province, on the border with Nicaragua. Lisandro Rosales, head of the country's Contingencies Commission said a red alert had been extended from six provinces to the whole country.
"A lot of rivers have high levels because of soil saturation due to frequent rains since May," said Randolfo Funez, operations director of the Contingencies Commission.
In the capital of Tegucigalpa, thousands of residents rushed to gas stations, supermarkets and banks after authorities recommended people stock up on food and other supplies and warned of three days of torrential rains.
Authorities said classes would be suspended until further notice and that 15,000 schools had been made available to be used as shelters.
A tropical storm warning also was in effect for the coast of Belize. Forecasters said the storm will reach the Guatemala-Belize border by Saturday night.
Nicaraguan President Daniel Ortega ordered the preventive measures and "all emergency structures are on alert," Lt.
Col. Freddy Herrera told The Associated Press by telephone.
"We have evacuated people from the region of Cabo Gracias a Dios and the Miskito Cays" in the same region.
Flights into the area were suspended due to limited visibility, though the winds were moderate, the military said.
In Honduras, the government declared a state of preventive alert throughout the country and Defense Minister Marlon Pascua said the army was ready to help civil defense actions.
The defense minister said armed forces were ready, and the Red Cross reported 3,000 aid workers in place. Civil defense officials in El Salvador were taking precautions, including canceling classes in high-risk areas, and Costa Rican authorities also reported being on a high level of alert for increased precipitation in flood-risk zones along the central Pacific coast.
Meanwhile far out over the Atlantic, Hurricane Lisa weakened to a tropical storm and was drifting slowly north with maximum sustained winds near 70 mph (110 kph).
