Fiona strengthens into Category 4 storm and heads to Bermuda

Fallen palm trees after Hurricane Fiona passed though Providenciales, Turks and Caicos Islands (Vivian Tyson/AP)

Hurricane Fiona strengthened into a Category 4 storm on Wednesday after devastating Puerto Rico, then lashing the Dominican Republic and the Turks and Caicos Islands.

The storm, which is forecast to squeeze past Bermuda later this week, has been blamed for directly causing at least four deaths in its march through the Caribbean, where winds and torrential rain in Puerto Rico left a majority of people on the US territory without power or running water.