Eastern United States hit by winter storm
A swathe of the US eastern seaboard is being engulfed in a winter storm dumping heavy snow as it sweeps north.
Hundreds of domestic and international flights have been cancelled and severe weather warnings are in place from Georgia to Vermont as temperatures continue to plummet.
Blizzards dropping up to 1ft (31cm) of snow are hitting New York and parts of New England.
South Carolina had its first Christmas snow for several decades.
Transport officials in Washington DC deployed 200 salting lorries, snow ploughs and other equipment. However, by Sunday afternoon the city seemed to have missed the worst of the storm.
Up to 20in of snow were expected in some areas, including Philadelphia.
Blizzard warnings were in effect for Rhode Island and most of eastern Massachusetts including Boston. Forecasters were predicting more than 1ft of snow from midday on Sunday onwards.
The National Weather Service said the monster storm was the result of a low pressure system off North Carolina's coast which was moving north-east and intensifying.
British Airways and Virgin are among operators cancelling flights into many eastern destinations, including New York.
States of emergency
Snow began falling around New York City late on Sunday morning and up to 18in was predicted to fall on the New Jersey coast, with wind gusts of more than 40mph (64km/h).
New York Mayor Michael Bloomberg said: "Unfortunately our city is directly in the path."
About 2,400 street cleaners have been called in to clear snow in the city.
Maryland, Virginia and North Carolina had declared states of emergency by Sunday.
Virginia Governor Bob McDonnell told the Weather Channel that snow driven by strong winds would make travel conditions hazardous.
"We're urging extreme caution in travel. Try to get home early and if you don't have to travel don't go," he said.
As conditions worsened on Sunday, transport services were being cancelled.
National rail operator Amtrak announced it was cancelling services between Boston and New York City and from Boston to Portland, Maine.
It said trains between Washington and New York had not been affected as of Sunday afternoon.
Delta Airlines cancelled about 850 flights mainly from North and South Carolina up to Boston.
Delta spokesman Kent Landers said the airline expected cancellations on Monday morning across the north-east but "certainly by Tuesday morning we are aiming to resume normal operations throughout the east coast".
Continental Airlines cancelled 250 flights from Newark Liberty International Airport outside New York City.
United Airlines also cancelled dozens of Sunday flights from Newark, Philadelphia, New York's LaGuardia and JFK, Boston and other airports. AirTran and Southwest Airlines also cancelled flights.
Bus companies also cancelled services up and down the east coast, affecting thousands of travellers.
The American football game between the Philadelphia Eagles and Minnesota Vikings was postponed in Philadelphia because of a blizzard.