Hurricane Matthew - now downgraded to a tropical storm - is churning out to sea off the coast of North Carolina after carving a path of death and destruction across Haiti, Cuba, the Bahamas and the southeast coast of the United States.

US President Barack Obama has declared states of emergency across the region where at least 17 people were killed and more than 2 million homes and businesses lost electricity. The emergency declaration frees up federal dollars to help states repair damaged infrastructure and remove debris.

"People were hit," President Barack Obama said in Chicago. "They weren't hit as directly as we had feared, but it has left a lot of devastation in its wake. Lives have been lost, property has been severely damaged and there's still continuing risk of flooding going on."

The ferocity of the rain caught some people by surprise.

Ezekiel Crowe, 10, escaped the floods in Fayetteville, North Carolina, on Saturday with his parents and seven siblings when a police boat plucked them from an apartment as the waters rose.

"I was scared. I was scared," he said. "And I thought, I thought the world was going to end. But it didn't."

Matthew raked the region with torrential rain - as much as 18 inches (46 cm) - and fierce winds topping 100 mph (160 kph). For all the death and destruction, however, it could have been worse, as the eye of the storm stayed offshore as it swept up the coast.

Devastation across the Americas' poorest nation

In Haiti, it was worse. Much worse. 

At least 1,000 people have died, according to a tally of numbers collected by local authorities. On Sunday the government started burying the dead in mass graves.

A United Nations Environmental Program (UNEP) employee in Port-a-Piment likened the catastrophe to a nuclear bomb explosion.

The poorest nation in the Americas is now facing a public health crisis, with a cholera epidemic spreading through rural communities lacking clean water, food and shelter. The sickness spreads through contaminated water, causing severe diarrhea. It can kill within hours if not treated.

Hospital resources are stretched. Basic resources are lacking, as well as cars and ambulances. Hospital staff members report that patients have been coming from miles away, often carried in on camp beds by family members.

Across the south of the country, electricity is out and water and food are scarce. Officials say that young men in villages along the road between the hard-hit cities of Les Cayes and Jeremie are putting up blockades of rocks and broken branches to halt convoys of vehicles bringing supplies.

"They are seeing these convoys coming through with supplies and they aren't stopping. They are hungry and thirsty and some are getting angry," said Dony St. Germain, an official with El Shaddai Ministries International.

There are already dire warnings that the hurricane's damage to Haiti's farms could lead to widespread famine if outside help isn't provided on a regular basis. "In terms of destruction - environmental and agricultural - I can tell you 2016 is worse than 2010," the UNEP employee said, referring to the devastating earthquake that hit Haiti in 2010, killing around 250,000 people.

"The country won't be able to recover in 10 years," Winthrop Athie, a founding member of Seguin Foundation, a group dedicated to preserving Haiti's natural resources, told the AFP news agency. "We need a Marshall Plan, we need to create jobs and rapidly. If we continue to get the same aid, there'll be no results and famine will grip the country."

bik,dm/lw (AP, Reuters, AFP, dpa)