Powerful Hurricane Beryl churned along Jamaica's southern coast on Wednesday, battering the island with dangerous winds and sea surge after leaving a trail of destruction and at least seven people dead in the Caribbean.

The eye of the Category 4 hurricane has not yet breached the shore of Jamaica but could in the coming hours, and is expected to approach or even make landfall in the Cayman islands overnight before moving onward to Mexico's Yucatan Peninsula, the US National Hurricane Center said.

The storm is the first since NHC records began to reach the Category 4 level in June and the earliest to reach Category 5 in July.

Ahead of Beryl's arrival, people across Jamaica removed boats from the water and rushed to buy food, water, gasoline and other essentials.

As of Wednesday afternoon the storm was packing maximum sustained winds of 140 mph (220 kph), said the NHC. Hurricane conditions are spreading through the island, it said.

Prime Minister Andrew Holness declared a curfew from 6:00 am to 6:00 pm across the island of 2.8 million and urged Jamaicans to comply with evacuation orders.

"If you live in a low lying area, an area historically prone to flooding and landslide or if you live on the banks of a river, I implore you to evacuate to a shelter, or to safer ground," he said in a video posted to social media.

Desmon Brown, manager of the National Stadium in Kingston, said his staff has scrambled to be ready.

"We've taped up our windows, covered our equipment -- including computers, printers and that sort of thing. Apart from that, it's mainly concrete so there's not much we can do," Brown told the Jamaica Observer newspaper.

Mexican officials were meanwhile scrambling to prepare for Beryl, which is expected to hit somewhere between the well-known tourist hotspot of Tulum and the town of Felipe Carrillo Puerto, according to Civil Protection national coordinator Laura Velazquez.

Beginning Thursday "we will have intense rains and wind gusts" she said, announcing the deployment of hundreds of military personnel, marines and electricity workers in anticipation of damage.

The government has prepared 112 shelters with a capacity for some 20,000 people and suspended school in the state of Quintana Roo where Beryl will hit.

- 'No communication' -

Beryl has already left a trail of death with at least three people killed in Grenada, where the storm made landfall Monday, as well as one in St Vincent and the Grenadines and three in Venezuela.

Grenada's Prime Minister Dickon Mitchell said the island of Carriacou, which was struck by the eye of the storm, has been all but cut off, with houses, telecommunications and fuel facilities there flattened.

The 13.5-square mile (35-square kilometer) island is home to around 9,000 people. At least two people there died, Mitchell said, with a third killed on the country's main island of Grenada when a tree fell on a house.

In St. Vincent and the Grenadines, one person on the island of Bequia was reported dead from the storm, while a man died in Venezuela's northeastern coastal state of Sucre when he was swept away by a flooded river, officials there said.

- Climate change -

It is extremely rare for such a powerful storm to form this early in the Atlantic hurricane season, which runs from early June to late November.

Warm ocean temperatures are key for hurricanes, and North Atlantic waters are currently between two and five degrees Fahrenheit (1-3 degrees Celsius) warmer than normal, according to the US National Oceanic and Atmospheric Administration (NOAA).

UN climate chief Simon Stiell, who has family on the island of Carriacou, said climate change was "pushing disasters to record-breaking new levels of destruction."

"Disasters on a scale that used to be the stuff of science fiction are becoming meteorological facts, and the climate crisis is the chief culprit," he said Monday, reporting that his parents' property was damaged.

© Agence France-Presse