The US President Barack Obama om Saturday declared emergency in three States of New York, Virginia and Massachusetts as hurricane Irene is likely to hit the eastern shores of the United States. Mandatory evacuations have been ordered all along the Eastern Seaboard and in low-lying areas of New York city ahead of Irene's arrival with a sustained wind speed of 100 miles per hour. Irene, which has already caused havoc in the Caribbean, is expected to hit the coast of North Carolina before barrelling northwards towards Washington and New York City. New York authorities have already evacuated a quarter of a million residents and ordered complete shut down of the mass transit system in an unprecedented preparations to brave out the Hurricane Irene . Over 250,000 people in low-lying areas of Manhattan, Brooklyn and Queens have been evacuated to safer places.Neighbouring New Jersey ordered evacuation of 750,000 people out of the Cape May area.Cutting short his summer vacation, President Barack Obama has returned with his family to the WhiteHouse as millions of people along the eastern coast geared up to face hurricane Irene.In an address to the nation, President Obama urged Americans to take Irene seriously.Mr Obama has held conference call with his top officials and reviewed the preparedness to deal with hurricane Irene. Organizations from the Pentagon to the American Red Cross were positioning mobile units and preparing shelters with food and water. York, Virginia and Massachusetts as hurricane Irene is likely to hit the eastern shores of the United States. Mandatory evacuations have been ordered all along the Eastern Seaboard and in low-lying areas of New York city ahead of Irene's arrival with a sustained wind speed of 100 miles per hour. Irene, which has already caused havoc in the Caribbean, is expected to hit the coast of North Carolina before barrelling northwards towards Washington and New York City. New York authorities have already evacuated a quarter of a million residents and ordered complete shut down of the mass transit system in an unprecedented preparations to brave out the Hurricane Irene . Over 250,000 people in low-lying areas of Manhattan, Brooklyn and Queens have been evacuated to safer places.Neighbouring New Jersey ordered evacuation of 750,000 people out of the Cape May area.Cutting short his summer vacation, President Barack Obama has returned with his family to the WhiteHouse as millions of people along the eastern coast geared up to face hurricane Irene.In an address to the nation, President Obama urged Americans to take Irene seriously.Mr Obama has held conference call with his top officials and reviewed the preparedness to deal with hurricane Irene. Organizations from the Pentagon to the American Red Cross were positioning mobile units and preparing shelters with food and water.