WASHINGTON — At least four people were killed as Hurricane Laura battered the US state of Louisiana early Thursday, causing flash floods, severe damage to buildings and power cuts to half a million homes.

The storm made landfall at 1 a.m. near Cameron, Louisiana, about 35 miles east of the Texas border.

The storm is one of the strongest to ever hit the US Gulf Coast, striking at category four packing up winds up to 150mph (240km/h). It weakened and was downgraded to a Category 2 hurricane Thursday morning as it headed northward, but it still had sustained winds of more than 100 mph.

Heavy rain was predicted to be widespread across the west-central Gulf Coast with five to 10 inches falling over a broad area, and locally up to 18 inches, leading to flash flooding.

Laura's storm surge has not reached the levels feared but is still considered life-threatening, and could spread 40 miles (65km) inland.

Half a million residents had been told to leave parts of Texas and Louisiana.

Louisiana Governor John Bel Edwards said early on Thursday: "We've had daylight now for a couple of hours. It appears there is more structural damage from the wind and a little less flood damage than we anticipated."

He confirmed the first fatality in his state, adding: "I suspect that won't be the last, although I pray that we don't have more."

President Donald Trump had spoken to the governors of Texas and Louisiana, the White House confirmed, and encouraged "all in the storm's path to listen to the safety guidelines of state and local officials".

Laura and another storm, Marco, earlier swept across the Caribbean, killing 24 people. — Agencies