Updated

President Barack Obama has declared an emergency for North Carolina that is expected to be hit by Hurricane Irene over the weekend.

Obama on Thursday night ordered federal aid to supplement state and local responses to the storm.

The Department of Homeland Security and Federal Emergency Management Agency (FEMA) can coordinate all disaster relief efforts.

It also means the state is eligible for federal funds to help in cleanup and other needs.

Irene is tightening its aim on the Eastern Seaboard. It threatens up to 65 million people along a shore-hugging path from North Carolina to New England.

Gov. Beverly Perdue's staff is taking the blame for failing to alert the North Carolina public sooner that the governor had declared a state of emergency for nearly 40 eastern counties for the approaching Hurricane Irene.

Perdue's press office announced late Thursday morning her declaration, which sets in motion mechanisms for state emergency officials to respond to the storm, activate the National Guard and lay the groundwork for Perdue to seek federal financial assistance.

But Perdue had actually signed the declaration early Wednesday evening and didn't mention it at a media briefing Thursday morning.

Perdue spokesman Mark Johnson said it was the press office's mistake that the declaration wasn't announced sooner. He said the governor didn't mention it because she believed a news release about it already had been sent.

Gov. Chris Christie asked all seaside visitors to voluntarily go home by Friday as Hurricane Irene took aim at New Jersey, and the state's southernmost county, Cape May, took the more drastic step of ordering a mandatory evacuation of all tourists and residents -- setting up what could be the biggest storm-related evacuation in state history.

Cape May County, in its emergency proclamation Thursday afternoon, ordered tourists on the barrier islands and any other visitors to leave by day's end. Mainland residents of the county, much of it a peninsula, were told to leave Friday morning.

The county at the exposed southern tip of New Jersey has about 100,000 year-round residents but its population swells to several times that size in the summer, when seasonal residents and sun-seeking tourists fill up resort towns like Ocean City, Wildwood and Cape May.

Preparations for Irene picked up pace Thursday as forecasts showed the storm was increasingly likely to have major effects across the state, not just on the shore. Some projected paths showed it making landfall around Cape May. Christie asked for voluntary evacuations of the entire 130-mile Atlantic shoreline as well as other coastal areas, especially barrier islands, by noon Friday.

He said Irene was poised to be a "serious, significant event" this weekend, with flooding a threat across the entire state. The National Weather Service issued a hurricane watch for most of the state's coast.

"Do not try to ride it out. It is not the smart thing to do," Christie told a news conference Thursday at the State Police Regional Operations Intelligence Center. Christie set an example by having his family leave the governor's summer residence on Island Beach State Park on Thursday.

He said he could make evacuations mandatory if not enough people heeded the warning.

The governor said he could call the National Guard to help with storm duty; up to 6,000 members are available. The state was also preparing for the possibility of moving prison inmates out of low-lying modular units.

Atlantic City's casinos began canceling bus trips as gamblers scrapped reservations. It's still possible the casinos could shut down for the storm -- something that has not happened since Hurricane Gloria in 1985.

In flood-prone Passaic County, jail inmates were being scheduled to fill sandbags Friday and Saturday in Little Falls and Pompton Lakes.

Inspectors were also making sure the state's four nuclear power plants were secured for the storm.

Rutgers University switched dorm move-in day for its New Brunswick-Piscataway campus from Sunday to Saturday in hopes of missing the storm; Seton Hall University in South Orange made a similar decision, telling students that they should play to arrive before 2 p.m. Saturday or wait until Monday.

The Federal Emergency Management Agency said it would send workers to every state along the East Coast and was setting up a stockpile of supplies including ready-to-eat meals, water and generators at New Jersey's McGuire Air Force Base.

Skip Sindoni, a spokesman for PSEG Nuclear, which operates three of the state's four nuclear reactors, said inspections were under way to make sure the plants' water-tight doors are working and to secure anything that could be loosened by the wind. He said the plants would be taken offline if it looks like hurricane-force winds are within two hours. He also said they could be shut down if floodwater reaches a certain level.

Gov. Andrew Cuomo declared a state of emergency Thursday in New York and directed state agencies to prepare to help with the storm expected to hit New York City and Long Island this weekend with heavy rains and high winds.

According to the governor's office, State Police are getting aviation, marine, dive, and communications units ready if needed. The Division of Military and Naval Affairs is developing plans to put hundreds of troops on duty for work with state and city agencies as required.

From the eastern tip of Long Island to New York City and the suburbs to the north, officials were warning residents to gather basic supplies.

Officials also were positioning emergency-response equipment like boats and helicopters and warning of disruptions to public transportation, with subway officials saying they could shut down the entire system if the rain and wind is severe enough.

New York City Mayor Michael Bloomberg said that he expected to make a decision by late Friday whether residents in the city's so-called "Zone-A" would need to evacuate ahead of the storm that's now expected to hit the city Sunday. That zone includes neighborhoods along the coast, such as Battery Park City in lower Manhattan, Coney Island in Brooklyn and Far Rockaway in Queens.

Bloomberg said he would issue an executive order instituting a forced evacuation only in the worst of circumstances. A suggested evacuation is more likely, he said.

The city has moved boats to police station houses in low-lying areas, hired emergency forest contractors and topped off hospital emergency generators with fuel in anticipation of the storm.

Department of Sanitation workers have been asked to be on the lookout for any street debris that could clog drainage.

Bloomberg said that while Long Island could face a Category 2 hurricane, New York City is not expected to be struck by the brunt of it. Instead, forecasts call for the city to see tropical storm conditions with heavy rains and winds of 60 mph or more, he said.

Meanwhile, on Long Island, Suffolk County Executive Steve Levy and other elected officials asked for voluntary evacuations of beach communities on western Fire Island, a popular summer destination. They said they were monitoring the weather to determine whether to call for a mandatory evacuation early Friday.

Officials in neighboring Nassau County were expecting to be in the direct path of the hurricane, and called for beach communities to begin preparing for possible evacuations. One community, the town of Hempstead, was pulling its boats out of the Atlantic Ocean and advising boaters to do the same.

"We're treating Irene as a war and we're ready for battle," said Town Supervisor Kate Murray.

Elsewhere on Long Island, New York's militia aviation units, vulnerable to high winds, were monitoring conditions Thursday, preparing to move rescue helicopters and planes upstate and out of the storm's path if needed, said Lt. Col. Richard Goldenberg, spokesman for the New York Division of Military and Naval Affairs.

North of the city in the Hudson River valley, Ulster County Executive Mike Hein asked city and state officials to authorize releases from two massive reservoirs that provide drinking water to the city -- a move meant to free up storage space and reduce flooding downstream if the storm dumps heavy rain.

The Ashokan Reservoir is at 94 percent capacity and the Rondout Reservoir at 97 percent, Hein said.

Gov. Dannel P. Malloy declared a state of emergency in Connecticut as residents stocked up on generators and other provisions Thursday and officials warned they should prepare for potentially prolonged power outages from Hurricane Irene, which threatened to dump up to a foot of rain on this already saturated state.

The declaration signed by the governor gives him a number of emergency powers, including the ability to order evacuations and direct civil preparedness forces into action.

"There's no way that looking at any of the maps we're seeing now that one could feel secure that we'll dodge this ... We're becoming more certain that we're likely to be impacted," Malloy said during a live, televised briefing at the emergency operations center. He urged residents to take the storm "as seriously as any event we've ever prepared for."

Malloy said this has been the clearest warning about a major hurricane hitting Connecticut, giving state and local officials, as well as the utilities, time to prepare for the storm. The electric and gas utilities have detailed response plans, including contracting with tree removal crews in anticipation of downed limbs and trees, he said.

Connecticut Light & Power, which serves 1.2 million customers, said it was cancelling vacations, putting all its personnel on standby and coordinating with sister companies in Massachusetts and New Hampshire to have additional crews available to restore power.

Malloy has urged local governments to clear drainage facilities ahead of the storm, which is projected to approach the state on Sunday. While the track and intensity of the storm remain uncertain, state officials said it could drop 6-10 inches of rain with more than a foot in isolated areas.

"To put it as delicately as we can, we take this threat very, very seriously," Malloy said. "We believe that the time to prepare for what might be an eventuality is now."

Gov. Jack Markell has declared a state of emergency for Delaware as Hurricane Irene approaches.

He has also ordered that visitors to coastal areas of the state must leave. Residents of those areas, as of Thursday evening, are allowed to stay.

Virginia Beach officials have ordered a mandatory evacuation for a section of the city in preparation for Hurricane Irene.

The evacuation for Sandbridge is effective at noon Friday. Virginia Beach officials ordered the evacuation late Thursday.

Gov. Bob McDonnell declared a state of emergency Thursday, but did not order an evacuation. He said he would leave that up to local officials.

Emergency officials are warning residents to prepare for massive power outages, flooding and damage from Hurricane Irene, a Category 3 storm that is expected to hit Virginia late Saturday or early Sunday.

With Hurricane Irene taking aim at the Maryland shore, officials ordered thousands of residents and visitors to leave Ocean City while Gov. Martin O'Malley warned of the dangers of the "monster" storm.

O'Malley declared a state of emergency Thursday. He warned state residents to prepare for what he called a large, deadly and "slow-moving hurricane that is bearing down on the state of Maryland."

The governor said Irene's epicenter is expected to arrive off the coast of Ocean City, with the eye wall possibly even over the beach community by 2 a.m. Sunday.

Ocean City Mayor Rick Meehan said Thursday there were probably about 125,000 to 150,000 people in Ocean City. The city has about 7,000 residents.

Meehan said the last time Ocean City ordered an evacuation was in 1985 for Hurricane Gloria.

The Associated Press contributed to this report.