Hurricane Maria has knocked out power across the island of Puerto Rico, home to 3.5m people, officials have said.
Flash flood warnings cover the entire island, which continues to be lashed by heavy rain in the storm’s wake.
Meanwhile more pictures are emerging of widespread destruction on the small island of Dominica, hit on Monday.
Maria, now a category three storm, is now lashing the Dominican Republic further west and heading towards the Turks and Caicos Islands.
It is the second devastating storm to hit the Caribbean this hurricane season – the first being category five Irma earlier in September.
‘Our island destroyed’
Puerto Rico Governor Ricardo Rossello described the hurricane as “the most devastating storm in a century” and said that Maria had hit the island’s electricity grid so badly that it could take months to restore power.
The storm is being blamed for at least 10 deaths across the Caribbean. In Puerto Rico one man died after being struck by a board he had used to cover his windows.
The authorities have warned people to move to higher ground amid “catastrophic” flooding, and with up to 30 inches (76cm) more rain predicted by Saturday.
Images shared on social media show roofs being stripped away as winds as strong as 140 mph (225 km/h) whipped trees and power lines in Puerto Rico’s capital city, San Juan.
“God is with us; we are stronger than any hurricane,” Mr Rossello said. “Together we will rise again.”
The governor has asked President Donald Trump to declare the island a disaster area after the storm unleashed heavy flooding and life-threatening winds, and damaged infrastructure across the territory.
The US president is yet to do so, but has made federal emergency aid available.