Barack Obama has warned Americans to take Hurricane Sandy seriously as authorities started shutting down the eastern seaboard ahead of its arrival. Several states have declared emergencies, with tens of millions of people affected as schools are closed and transport services suspended. Experts fear Sandy may become a super-storm when it makes landfall later. Some election rallies have been called off, with Mr Obama warning affected citizens to take precautions. International travel has been badly affected. Air France, British Airways and Virgin Atlantic grounded Monday's transatlantic flights to and from East Coast cities, including New York, Baltimore, Newark, Washington, Boston and Philadelphia. Sandy has already killed 60 people as it swept through the Caribbean during the past week. At 02:00 EDT (06:00 GMT), the storm was turning north, its eye swirling about 425 miles (760km) south-east of New York City, according to the National Hurricane Center. With winds of 75mph, Hurricane Sandy, dubbed "Frankenstorm", is expected to bring a "life-threatening" surge flood to the mid-Atlantic coast, including Long Island Sound and New York Harbour. The winds are expected to strengthen when Sandy makes landfall anywhere between Virginia and southern New England on Monday. The prospect of merging with a wintry storm coming from the west during a full moon has many fearing dangerous high tides. Sandy is some 520 miles (835km) across. It is also very slow, moving north-east at just 15mph, and could linger over as many as 12 states for 24-36 hours, bringing up to 25cm of rain, 60cm of snow, extreme storm surges and power cuts. States of emergency have been declared in Maryland, New York, Pennsylvania, Virginia, Washington DC and parts of North Carolina.
