NEW YORK (NYTIMES) - Hurricane Delta intensified into a Category 4 storm on Tuesday (Oct 6) and was expected to remain "extremely dangerous" as it reaches Mexico by early Wednesday, the US National Hurricane Centre said.

The storm, the ninth named hurricane of the season, was about 346km east-southeast of Cozumel, Mexico, the centre said. As of Tuesday afternoon, Delta had maximum sustained winds of 145mph with higher gusts.

The government of Mexico had issued a hurricane warning from Tulum to Dzilam, the centre said, and tropical storm warnings were in effect for a portion of western Cuba, Isle of Youth, Punta Herrero to Tulum, and Dzilam to Progreso.

Government officials ordered non-essential businesses to close as emergency crews helped evacuate inhabitants from low-lying coastal areas to storm shelters.

"It's ideal conditions for rapid intensification - warm water temperatures, negligible wind chill," said Mr Dennis Feltgen, a meteorologist and spokesman for the National Hurricane Centre.

"This has turned into a very dangerous, very serious hurricane."

Residents across the region scrambled on Tuesday to prepare for the storm's arrival, stocking up on days' worth of groceries, hardware materials and petrol, and pulling boats from the water and moving them to higher ground.

Scores of hotels along the Caribbean coast, including popular tourist destinations such as Cancun, Playa del Carmen and Tulum, were moving their guests to shelters.

"The most important thing is to take care of everyone's life so that we don't lose anybody," said Mr Carlos Joaquin, the governor of the state of Quintana Roo, where the hurricane was expected to make landfall early on Wednesday.

The impact with the Yucatan Peninsula will most likely cause the storm to weaken, possibly to a Category 3 storm, Mr Feltgen said.

But the conditions are ideal for it to strengthen back to a Category 4 as it passes through the southern Gulf of Mexico and approaches the United States as a "major hurricane".

Delta is expected to approach the northern Gulf Coast later this week.

While the exact track remains uncertain, there is a risk of dangerous storm surge, wind and rainfall along the coast from Louisiana to the western portions of the Florida Panhandle beginning Thursday night or Friday.