US President Barack Obama has declared a state of emergency in eight states including New York, Virginia, Massachusetts and Connecticut as hurricane Irene hit North Carolina with high winds and heavy rain resulting in power cuts to thousands of homes and killing at least two people.

While Obama declared emergency in New York early in the day, the US President signed off on the emergency declaration in Virginia, Massachusetts, Connecticut, Rhode Island, New Jersey and New Hampshire, after he returned on Friday night cutting short his summer vacation.

Emergency in North Carolina was declared earlier. The possibly devastating hurricane is expected to follow the path of densely populated areas of eastern coast from North Carolina to New York and Rhodes.

"The President reiterated that we know that this storm's impacts will continue to be felt throughout the weekend and that we still have work ahead of us to support potentially impacted states and communities," the White House said in a statement after Obama reviewed preparedness of his administration for hurricane Irene.

Obama went to the National Response Coordination Centre to participate in a nationwide videoconference on hurricane Irene preparedness, attended by several governors and top officials of his administration.

"The President also asked states if there were any unmet needs, and while no immediate additional requirements were identified, he directed Administrator Fugate and Secretary Napolitano to continue to remain vigilant as we move into the next phase of this storm, including additional sheltering needs as the storm progressed," the statement said.

Authorities confirmed at least two deaths as the hurricane hit North Carolina. The Defense Secretary, Leon Panetta, issued a prepare-to-deploy order for 6,500 active duty troops from all the services to support hurricane relief efforts if ordered.

"It is a big storm. It's going to cover a lot of large geographic area, a lot of population. One concern I have is that once the storm has immediately passed, that people don't forget about the after effects. There can be flooding. There can be surge. We think there could be a lot of power outage associated with that," the Secretary of Homeland Security, Janet Napolitano, told the CNN in an interview.

Obama's action authorises the Department of Homeland Security, Federal Emergency Management Agency (FEMA), to coordinate all disaster relief efforts, which have the purpose of alleviating the hardship and suffering caused by the emergency on the local population and to provide appropriate assistance for required emergency measures, to save lives, to protect property and public health and safety, and to lessen or avert the threat of a catastrophe in these three States.

Governors of Florida, North Carolina, Virginia, Maryland, Delaware, New Jersey, Connecticut, and New York have already declared states of emergency as hurricane Irene nears land.

Federal storm-surge maps showed the potential for four-to 10-foot surges across a massive swath of the eastern United States, with potentially disastrous impacts in eastern North Carolina, the Tidewater area of Virginia, as well as the Potomac River that runs through Washington. Tens and thousands of people across the east coast have been evacuated from the low-lying areas.

"It looks like the track of Irene is going to have a major impact along the East Coast starting in the Carolinas all the way up through Maine," said Craig Fugate, director of the Federal Emergency Management Agency.

Residents and businesses along the East Coast should be taking steps now to prepare for severe weather and following the instruction of their local officials, including any evacuation orders," he said.

"Those in the path of the storm should make sure that you are also taking necessary and commonsense precautions such as having an emergency plan, such as having some emergency supplies, some food, some water, a flashlight with batteries in case we lose power.”

"We do anticipate a significant amount of power outage with this particular storm," said Napolitano.

"This is a very serious and deadly storm. This is the real thing. And people are very right to take it seriously," said the Maryland Governor, Martin O'Malley.