He said no one was inside the station, where the Marines, Air Force and Navy also recruit.
"I was up on the 44th floor and I could feel it. It was a big bang," said Darla Peck, 25, of Portland, Oregon.
"It shook the building. I thought it could have been thunder, but I looked down and there was a massive plume of smoke so I knew it was an explosion," said Terry Leighton, 48, of London, who was staying on the 21st floor of the Marriott.