Hurricane Matthew has killed at least 14 people as it battered the US east coast.
As the storm hit there were major floods and power outages in Florida, Georgia, and North and South Carolina.
Matthew - which was a category 5 storm when it hit Haiti last week killing nearly 900 people - has since been downgraded to a post-tropical cyclone but at one point hit wind speeds of over 157mph.
Thousands of residents in Florida have been spared the worst of hurricane Matthew as the storm's centre hovered just offshore.
Nearly 600,000 homes and business were left without power as high winds of up to 107 mph thrashed the area around Daytona beach, whipping up storm surges, toppling trees and ripping off roofs.
However many of the most populous areas were spared as the storm swerved away from shore, avoiding many of the state's most heavily-populated areas.
President Obama said the new areas of concern are now Jacksonville in northern Florida and the neighbouring state of Georgia as Hurricane Matthew moves north.
Florida governor Rick Scott has also reiterated warnings to thousands of residents ordered to evacuate, saying: "Remember, it could be the worst of it is yet to come."
Matthew - which was a category 5 storm when it hit Haiti last week killing nearly 900 people - made landfall in the States on Friday.
As Hurricane Matthew approaches Florida, its 140-mile-an-hour winds have already left behind a trail of destruction in Haiti.
Residents told to fully prepare for the arrival of the hurricane with warnings its impact could be "devastating".