A strong earthquake struck the US east coast and was felt as far away as Canada today, shaking buildings in many cities, delaying flights and trains and sending thousands of frightened workers into the streets.
There were no reports of major damage or injuries from the 5.9 magnitude quake, which the US Geological Survey said was centered in Mineral, Virginia, at a very shallow depth of 0.6 mile (1 km).
The Pentagon and the US Capitol were briefly evacuated in Washington, and thousands of panicked office workers scurried into the streets up and down the east coast as the lunchtime quake sent items crashing to the floor from store and office shelves.
"We were rocking," said Larry Beach, who works at the USAgency for International Development in downtown Washington, 133km from the quake's epicentre. "It was definitely significant."
Flights resumed after the quake grounded planes and delayed tens of thousands of passengers during the mid-afternoon travel rush.
Airline operations were halted in Washington, New York and Philadelphia for more than 90 minutes to allow runway, control tower and terminal inspections, federal and local transportation officials said.
Rail company Amtrak reduced speed between Washington and Baltimore, track crews inspected east coast stations and rails for damage and warned passengers to expect delays.
Two nuclear reactors at a power plant in Virginia went off line, while traffic lights were knocked out throughout Washington.
Three pinnacles in the central tower of the Washington National Cathedral, the highest building in the city, broke off in the quake, a spokesman said.
Chandeliers swayed in the US Capitol and the floor of the US Senate shook before staff headed for the doors. The US Congress is in recess.
"I thought at first somebody was shaking my chair and then I thought maybe it was a bomb," said Senate aide Wendy Oscarson-Kirchner.
Phone service was disrupted throughout the region as network congestion prevented mobile users from making calls. A Verizon Wireless spokesman said there were no reports of damage to its network but congestion disrupted service for about 20 minutes after the quake.
In New York, the tremors prompted evacuations of courthouses, City Hall and halted work at the World Trade Center construction site.
Fire department and police officials in Dutchess County, north of New York City, reported structural damage to some buildings.
"We're getting a lot of calls on buildings shaking but there's no report of any structural damage at this time. Just panicked people calling about buildings shaking," a spokesman for the New York City Fire Department said.
Buildings in Boston were evacuated, while the quake was felt as far away as Toronto.
Some people who experienced the swaying at their offices in Boston said they felt their stomachs turn.
"I thought I was dizzy and I needed to drink more water," said Heather Kennaway, a manager at Sportello, a local restaurant, who was unaware of the earthquake.
The earthquake was felt in Martha's Vineyard, where President Barack Obama was playing golf on his summer vacation at the time.
The quake was the largest in Virginia since 1897.
Vacationers at the Hamptons, the upscale resort on eastern Long Island, felt the earth shake. Many grabbed their mobile phones to make calls, while several began asking aloud whether a tsunami - a huge wave created by an underwater quake - was headed their way.
Earthquakes of magnitude 5.5 to 6 can cause damage to buildings and other structures, especially if shallow. The US east coast does not normally feel quakes of this strength.
The shallower a quake is, the more intense it is felt on the surface, and the potential for damage is greater.
Reuters