Story highlights Typhoon Melor has killed at least four people and prompted the evacuation of 734,000 people

Storm unexpectedly becomes stronger Tuesday morning as it nears another island

Flights have been canceled, schools closed and travelers stranded in ports

(CNN) Hundreds of thousands of people have been evacuated in the central Philippines, where a fierce storm is lashing coastal areas with heavy wind and rain.

Typhoon Melor has killed at least four people, caused power cuts and disrupted transportation after churning across several islands in the archipelago since Monday.

On Tuesday morning, the storm unexpectedly regained force, with its maximum sustained winds rising to 230 kph (143 mph), according to the U.S. military's Joint Typhoon Warning Center.

That made it the equivalent of a Category 4 hurricane just as it slammed into an area of the western island of Mindoro where tens of thousands of people live.

The storm, known in the Philippines as Nona, hasn't made any direct hits on major population centers. But it has battered communities along the many coastlines on its path.

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