A magnitude-5.8 earthquake has rattled the east coast of the United States.
The quake centred on the state of Virginia but was felt in Washington, where the Pentagon and US Capitol were evacuated, as well as in New York.
The National Cathedral was damaged and the Washington Monument closed. There were no immediate reports of injuries.
Federal officials said two nuclear reactors had been taken offline near the epicentre of the quake but that no damage had been reported.
A total of 12 nuclear plants declared "unusual events" after the quake.
The quake struck some 84 miles (135km) from south-west of Washington, at a depth of 3.7 miles (6km), the US Geological Survey (USGS) said.
Its epicentre was about 8km (five miles) from the town of Mineral, in the state of Virginia.
An initial measurement of 5.8 was later upgraded to 5.9, but later amended back to 5.8 by the USGS.
The quake was one of the most powerful on the east coast of the US since 1897, according to USGS records, matching the strength of a tremor in the state of New York in 1944.
Three aftershocks were recorded during Tuesday, the USGS said, the first two measuring 2.8 and 2.2. The third shock, at 20:04 local time (00:04 GMT on Wednesday), was a magnitude-4.8 tremor.Flights held
The main earthquake shook Washington DC for about 30 seconds at 13:51 on Monday (17:51 GMT), causing office buildings to sway and houses to shake.
The streets of the city filled with evacuated workers minutes after the quake, and police moved swiftly to cordon off key government institutions, restricting access to federal buildings on Capitol Hill.Continued