SAN JUAN, Puerto Rico (AP) — Tropical Storm Fred made landfall in the Dominican Republic on Wednesday, with forecasters warning that heavy rains could cause dangerous flooding and mudslides there and in the neighbouring country of Haiti.

After a quiet month of no named storms in the region, Fred became the sixth of the Atlantic hurricane season late Tuesday as it moved past the US Virgin Islands and Puerto Rico on a forecast track that would carry it toward Florida over the weekend.

Government crews with megaphones walked through impoverished neighbourhoods in the Dominican capital of Santo Domingo ahead of the storm urging those in low-lying areas to evacuate.

Tropical storm warnings were discontinued in the US territories after pelting the islands with rain, leaving some 13,000 customers without power in Puerto Rico.

Fred was centred 30 miles (50 kilometres) west of Santo Domingo, Dominican Republic, on Wednesday morning and moving west-northwest at 16 mph (26 kph), the US National Hurricane Center said. It had maximum sustained winds of 45 mph (75 kph).

The Dominican Republic, Haiti and central and eastern Cuba could get hit Wednesday, and people in Florida were urged to monitor updates. Forecasters said the centre of Fred was expected to move near the Turks and Caicos Islands and the southeastern Bahamas on Thursday, and move north of the northern coast of central Cuba on Friday.

Puerto Rico Governor Pedro Pierluisi closed government agencies on Tuesday at noon and officials noted that some gas stations had shut down after running out of fuel. The heaviest rain was expected to fall during the night, forecasters said.

Eight shelters were opened across the island, though officials said only about seven people had checked in by midevening.

“Do not wait until the last minute to mobilise,” said Nino Correa, Puerto Rico’s emergency management commissioner. “We don’t want to have fatalities.”

More than a month had passed since the last Atlantic storm, Hurricane Elsa, but this time of summer usually marks the start of the peak of hurricane season.

The hurricane centre issued warnings for Dominican Republic on the south coast from Punta Palenque eastward and on the north coast from the Dominican Republic/Haiti border eastward. A watch was in effect for Haiti from the northern border with the Dominican Republic to Gonaives and for the Cuban provinces of Ciego de Avila, Camaguey, Las Tunas, Holguin, Granma, Santiago and Guantanamo. Also included in the watch was the Turks and Caicos Islands and southeastern Bahamas.

The storm was expected to produce rainfall of two to four inches (five to 10 centimetres) over Puerto Rico and the Dominican Republic with up to six inches (15 centimetres) in some areas.