Hurricane Irma strengthens to Category 3 over eastern Atlantic

Hurricane Irma on Thursday strengthened into a Category 3 hurricane over the eastern Atlantic and was headed towards the Caribbean, the U.S. National Hurricane Centersaid in its latest advisory.

In an earlier statement at 11 a.m. ET, the NHC said Irma is "expected to be an extremely dangerous hurricane forthe next several days."

Irma is located about 3,000 kilometres east of theLeeward Islands with maximum sustained winds of 155 km/h, theMiami-based weather forecaster said.

NHC forecast models were showing it heading for the U.S. territory of Puerto Rico, the Dominican Republic and neighbouring Haiti with possible landfall by the middle of next week.