Tropical storm Wilma strengthened into Category 2 hurricane late Tuesday on a path that could threaten Florida by the weekend.

Wilma was expected to strengthen into a powerful Category 4 storm on the five-step scale of hurricane intensity, with winds over 209 kph by the time it crosses into the Gulf of Mexico on Friday.

Forecasters said Wilma was likely to spare the central part of the US Gulf coast and its oil industry, which has already been struck three times this year by Katrina, Rita and Dennis. But they warned it could threaten Florida by the weekend after passing between Mexico's Yucatan peninsula and Cuba.

Wilma is the 12th hurricane of the Atlantic Ocean season, tying a 1969 record.

Mexico issued a hurricane watch for parts of the Yucatan. Officials in Nicaragua and El Salvador monitored the storm's course closely. Heavy rain in Cuba triggered evacuation preparations in four southern provinces.

This year's June 1-Nov. 30 season already equaled the busiest on record, matching the 21 named storm systems of 1933.

Source: Xinhua/agencies