The Pentagon was evacuated early Tuesday afternoon moments after a 5.8 magnitude earthquake out of Mineral, Va. shook reinforced concrete walls of the building, sending panicked workers running for the exits.
Some of the nearly 20,000 people who work at the Pentagon every day feared the shaking was caused by another Sep. 11 style attack.
Fears of a terror attack were quickly dismissed after it became clear others around Washington D.C. and Virginia felt the tremors. The quake was felt as far away as New York City, North Carolina, Ohio and Illinois.
At the Pentagon black SUV's sped to the VIP entrance waiting to evacuate senior military officers. Marine helicopters circled above.
Cell phone signals were jammed as thousands of people gathering outside attempted to make calls to loved ones, friends, and colleagues.
Pipes burst on the second and third floors of the building. Safety workers were able to stop the flooding within an hour.
Local officials are recommending people stay away from the Metro system, which includes a stop directly under the Pentagon.
The quake felt like a low rumble that built to an eventual shake.
Fox News correspondents in the building witnessed items falls from shelves as they left the reporter's corridor.
An all clear has since been called and everyone has reentered the building.
Fox News' Justin Fischel contributed to this report.