Hundreds stranded in North Carolina floods after Hurricane Matthew

Matthew, the most powerful Atlantic storm since 2007, was downgraded to a post-tropical cyclone on Sunday.

The hurricane killed around 1,000 people in Haiti and United Nations Secretary-General Ban Ki-moon said some Haitian towns and villages had just about been 'wiped off the map.'

In the United States, the number of fatalities rose to at least 23, with nearly half in North Carolina.

After receiving as much as 18 inches (39 cm) of rain from Matthew over the weekend, North Carolina's skies were clear on October 10, but raging rivers and breached levees posed major problems.

"This storm is not over in North Carolina," Governor Pat McCrory told reporters in Fayetteville. "It's going to be a long, tough journey."

Eleven people have died in the state, officials said. With rivers rising, the governor said he expected deaths to increase.

The flooding prompted President Barack Obama to declare a state of emergency in North Carolina, making federal funding available to affected individuals in 10 counties hit by the storm, the White House said in a statement.

Some 2,000 residents were stuck in their homes and on rooftops in Lumberton, off the Lumber River, after the city suddenly flooded on the October 10, McCrory said. Air and water rescues would continue throughout the day, he said.

Many of the homes and businesses in Lumberton were flooded with several feet of water and residents were seen paddling about the town in small skiffs.

Major flooding was expected this week in central and eastern towns along the Lumber, Cape Fear, Neuse and Tar rivers. The National Weather Service said the Neuse River would crest on Friday night and forecast 'disastrous flooding.'

Emergency officials in North Carolina's Lenoir County issued a mandatory evacuation order for residents and businesses along the Neuse River.

Many coastal and inland communities remained under water from storm surge or overrun rivers and creeks.

McCrory told reporters that he had met with an elderly woman at a shelter who lost everything to floods.

"She's sitting in a school cafeteria at this point in time crying and wondering what her life is going to be all about," he said. "It breaks your heart."

In neighboring South Carolina, Governor Nikki Haley warned that waterways were quickly reaching capacity around the state.

"What might not be flooded today could be flooded tomorrow," Haley said at a news conference.

She said there had been at least three storm-related deaths, including one in which a person in a vehicle was swept away by floodwaters.

Warnings were also issued over downed power lines. An 89-year-old man in Florida was killed after touching a downed line, officials said.

While power was being restored in some areas, about 1.1 million people were still without power in Florida, Georgia, North and South Carolina and Virginia.

A federal judge granted a request from Florida's Democratic Party to extend the state's voter registration deadline by one more day, through Wednesday, because of the hurricane. Republican Governor Rick Scott had rejected demands from Democrats to extend the deadline.

Meanwhile, a hurricane watch was issued for Bermuda, which could be threatened by another tropical system, Nicole, that is expected to reach the Atlantic island later this week, the US National Hurricane Center said.