The FBI and U.S. Army have offices at the same building in New York City.

There has been an explosion reported at 26 Federal Plaza in downtown New York City on Wednesday afternoon at a building that houses both FBI and U.S. Army offices. One Injury was reported. 

Early reports suggest that an FBI agent set off his own flash bang grenade and was being transported to a hospital following the incident. 

"A small incendiary device went off inadvertently," a source told the New York Post. 

The man is in stable condition at Bellvue hospital, according to the Post. 

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