MINERAL, Virginia (AP) _ One of the strongest earthquakes ever recorded on the East Coast of the United States shook buildings and rattled nerves on Tuesday and forced the evacuations of parts of the Capitol, White House and Pentagon.

There were no immediate reports of deaths, but fire officials in Washington said there were at least some injuries.

The U.S. Geological Survey said the quake registered magnitude 5.8 and was centered about 40 miles (64 kilometers) northwest of Richmond, Virginia.

Two nuclear reactors at the North Anna Power Station, in the same county as the epicenter, were automatically taken off line by safety systems, said Roger Hannah, a spokesman for the U.S. Nuclear Regulatory Commission.

Around Mineral, Virginia, a small town close to the epicenter, people milled around in their lawns, on sidewalks and parking lots, still rattled and leery of re-entering buildings. There was least one aftershock.

All over town, masonry was crumpled, and there were stores with shelved contents strewn on the floor. Several display windows at businesses in the tiny heart of downtown were broken and lay in jagged shards.

The earthquake came less than three weeks before the 10th anniversary of the Sept. 11 attacks, and in both Washington and New York it immediately triggered fears of something more sinister than a natural disaster.

Hours earlier, the strongest earthquake to hit Colorado in more than four decades startled people as it toppled chimneys, cracked walls and triggered minor rockslides in the arid, mountainous region on Monday night. No injuries were reported in the magnitude-5.3 quake.

Obama, who is vacationing on Martha's Vineyard, led a conference call Tuesday afternoon on the east quake earthquake with top administration officials, including the administrator of the Federal Emergency Management Agency.

At the Pentagon in Washington, a low rumbling built until the building itself was shaking, and people ran into the corridors of the complex. The shaking continued there, to shouts of ``Evacuate! Evacuate!''

The Park Service closed all monuments and memorials on the National Mall, and ceiling tiles fell at Reagan National Airport outside Washington. All flights there were put on hold.

Also in Washington, the National Cathedral said cracks had appeared in the flying buttresses around the apse at one end. ``Everyone here is safe,'' the cathedral said on its official Twitter feed. ``Please pray for the Cathedral as there has been some damage.''

In New York City, the 26-story federal courthouse in lower Manhattan, blocks from the site of the Sept. 11, 2001, terror attacks on the World Trade Center, began swaying, and hundreds of people streamed out of the building.

Also in New York, workers in the Empire State Building spilled into the streets, some having descended dozens of flights of stairs.

``I thought we'd been hit by an airplane,'' said one worker, Marty Wiesner.

Another, Adrian Ollivierre, a 28-year-old accountant who was in his office on the 60th floor when the quake struck, said: ``I thought I was having maybe a heart attack, and I saw everybody running. I think what it is, is the paranoia that happens from 9/11, and that's why I'm still out here _ because, I'm sorry, I'm not playing with my life.''

The last quake of equal power to strike the East Coast was in New York in 1944. The largest East Coast quake on record was a 7.3 that hit South Carolina in 1886.

Amtrak said its trains along the Northeast Corridor between Baltimore and Washington were operating at reduced speeds and crews were inspecting stations and railroad infrastructure before returning to normal.

More than 12 million people live close enough to the quake's epicenter to have felt shaking, according to the Geological Survey.

Social media site Twitter lit up with reports of the earthquake from people using the site up and down the U.S. eastern seaboard.

``People pouring out of buildings and onto the sidewalks and Into Farragut Park in downtown DC,'' tweeted Republican strategist Kevin Madden.

John Gurlach, air traffic controller at the Morgantown Municipal Airport was in a 40-foot (12-meter) tower when the earth trembled.

``There were two of us looking at each other saying, `What's that?''' he said, even as a commuter plane was landing. ``It was noticeably shaking. It felt like a B-52 unloading.''

Immediately, the phone rang from the nearest airport in Clarksburg, and a computer began spitting out green strips of paper _ alerts from other airports in New York and Washington issuing ground stops ``due to earthquake.''