Boston - A powerful ice storm knocked out power to more than 1 million homes and businesses across New York and New England on Friday, closing roads and forcing the state of Maine to shut government offices.

"This is a very, very serious situation right now," New Hampshire Gov. John Lynch said after declaring an emergency in his state, where as many as 320,000 customers lost power in what local authorities describe as the worst outages in three decades.

"I don't think anyone anticipated it would be as bad as it is," Lynch said.

Massachusetts deployed about 500 National Guard troops to clear roads and help residents, while utilities officials from across the region said outages could grow as gusts of wind continue to snap tree limbs and bring down power lines.

Power may not return to thousands in Massachusetts until Monday at the earliest, Gov. Deval Patrick said. "Many of us view that as an ambitious estimate at this point," he told a news conference.

Western and central regions of the state were hit hardest, including Leominster, a city of 41,000 people that helped to launch America's plastics industry in the 18th century and was completely in the dark.

National Grid Plc reported about 318,000 customers in New England without power and 190,000 in eastern New York, adding it could take several days to restore power.

With freezing weather forecast for the weekend, some residents stocked up on propane to fuel power generators to keep the heat on. Others filed into hotels or emergency shelters set up by the Red Cross in high schools.

Maine and Massachusetts declared states of emergency.

"It's going to be cold this weekend," said Steve Brady, a meteorologist at the National Weather Service's southern New England office, predicting temperatures well below freezing.

BROKEN TREES 'EVERYWHERE'

In New Hampshire, Northeast Utilities' Public Service Co reported that 300,000 customers had no power as crews work to remove piles of tree limbs. The utility warned customers that it could take days to restore power.

"I couldn't even sleep because the noise of the trees hitting the ground was so loud," said Samantha Appleton of Merrimack, New Hampshire. Power transformers "blew out everywhere. It looked like green lightning."

Andrew Manuse, editor of the Manchester Express newspaper, said trees were strewn "everywhere."

"One is laying on my fence," he said. "Power's out. Water's out. Heater's out. There's a tree on my neighbors roof. Thankfully, no one was injured."

In Maine, at least 215,000 were without power, mostly in southern and coastal areas, and the number was expected to rise, said Iberdrola SA's Central Maine Power Co.

"By our best estimate right now, this restoration is likely to last well into next week in many areas," said the utility's spokesman, John Carroll.

Maine Gov. John Baldacci shut government offices in the state, citing weather and power outages. "If you have neighbors who are vulnerable or who could be at risk, check on them," he told residents in a televised news conference.

In Vermont, state officials opened three emergency shelters and urged residents to stay off roads glazed in ice.