The death toll in the United States from Hurricane Irene has risen to 18, with four new fatalities reported in the state of Pennsylvania, US officials have said.

Six deaths have been recorded in North Carolina, where Irene made landfall early Saturday morning with 85-mile (140-kilometre) per hour winds, before heading up the eastern seaboard and scoring a rare hit on New York.

Four more deaths were recorded in Pennsylvania, including two men, one in a tent and another in a camper who were crushed by falling trees.

The toll rose from eight overnight with new fatalities including men hit by falling trees in North Carolina and Virginia, a woman in Maryland struck by a falling chimney, as well as one victim in New Jersey.

The breakdown of fatalities was: six in North Carolina, four in Virginia, four in Pennsylvania, one in New Jersey, and one each in Connecticut, Florida in Maryland.

The youngest fatalities were a boy killed by a falling tree in his apartment in Newport News, a city on a coastal peninsula in Virginia, and a girl who died in North Carolina.

“A 15-year-old girl was killed in a car accident on her way back from the beach after vacationing in North Carolina,” explained emergency official Patty McQuillan.

“The traffic light at the intersection was not working, the power was out.”

North Carolina emergency management spokesman Brad Deen said one of the six victims in his state was a man who had a heart attack on Friday while nailing plywood over his windows in preparation for the hurricane.

Two people were also killed in the state in separate driving accidents. Another North Carolina fatality was a man struck by a falling tree limb while outside feeding his animals.

Storm emergency not over: Obama

US President Barack Obama has said that the Hurricane Irene recovery effort could go on for days or weeks, but hailed the disaster response operation as an “exemplary” display of good government.

The president, who took pains to show Americans he was in charge of the emergency effort, amid memories of the botched response to Hurricane Katrina in 2005, also remembered the 14 people killed in the storm.

“I want people to understand that this is not over. Response and recovery efforts will be an ongoing operation,” Obama said in a short statement in the White House Rose Garden.

“I do want to underscore that the impacts of this storm will be felt for some time. And the recovery effort will last for weeks or longer. Power may be out for days in some areas,” Obama said on Sunday.

The president returned early from his vacation on Friday to deal with the Hurricane Irene response and led top homeland security officials in a massive federal and local operation on Sunday.

“Our thoughts and prayers are with those who’ve lost loved ones. And those whose lives have been affected by the storm,” Obama said.

“You need to know that America will be with you in your hour of need. While the storm has weakened as it moves north, it remains a dangerous storm that continues to produce heavy rains.”

Obama, flanked by Homeland Security Secretary Janet Napolitano and Federal Emergency Management Agency chief Craig Fugate, said he remained concerned by significant flooding and widespread power outages.