Hurricane Irene continues to pound the U.S. east coast with heavy rains and strong winds Sunday, leaving at least eight people dead in its wake and paralyzing ground and air traffic.

The National Hurricane Center says Irene is approaching New York with winds of 120 kilometers per hour. Forecasters say the upper floors of the city's many high-rise buildings will experience significantly stronger winds than at ground level.

Forecasters say Irene will move into southern New England in the northeastern U.S. by Sunday afternoon before reaching Canada Sunday night.

Effects of the storm have forced two nuclear reactors to cease operations – one in Maryland and one in New Jersey. Authorities say the facilities are safe, and no one has been harmed.

Irene blasted ashore in North Carolina early Saturday, flooding streets and toppling trees with winds of 140 kilometer per hour. The storm later moved into the Washington area, which has been hit with strong winds, heavy rain, localized flooding and falling trees.

Some 2 million homes and businesses are without power in the eastern U.S., with at least eight people killed. Tens of millions of people are in the path of the storm, which is passing through some of the country's most densely populated areas. Suspected tornadoes spurned by the hurricane destroyed homes in Delaware and Virginia. Tornado warnings are in place for New York and other areas.

The Hurricane Center warns of life-threatening waves and surf along the coast, with a storm surge raising water levels more than 2 meters in some areas. Rainfall of 25 centimeters or more could cause life-threatening flash floods and significant uprooting of trees. Many trees have already fallen where Irene has passed.

On Saturday, President Barack Obama visited the command center where senior emergency officials have been coordinating the country's response. He warned the situation would be critical for the next few days.

The U.S. Navy ordered the Second Fleet, stationed in Virginia, out to sea to avoid potential damage.

In New York, Mayor Michael Bloomberg ordered the city's first ever mandatory evacuation in low-lying areas of the city, including the Wall Street financial district. And in another first, New York's entire public transit system, including subway trains and buses have been shut down, as well as all three of New York's major airports.

Airlines have already canceled thousands of flights up and down the east coast, and train service in parts of the eastern region have been suspended.

The Red Cross said its response to Irene could be one of the largest it has undertaken in recent memory. The organization is responding to more than a dozen states, and says it could take weeks, even months, to be able to fully address the disaster.

Irene is the first hurricane to seriously threaten the United States in three years. Besides the U.S. fatalities, Irene has killed at least one person in Puerto Rico and two in the Dominican Republic, and destroyed homes in The Bahamas.

It came almost six years to the day after Hurricane Katrina flooded New Orleans, killing more than 1,800 people and forcing more than a million residents from their homes.