Update, 5:15 p.m.
: DCist reports that Lee was shot. Here's what Montgomery County Police Chief Tom Manger said, "He took three people hostage, near the lobby area of the entrance to the building. Over the past several hours, we've been in negotiations with the man. Approximately ten minutes ago, the suspect was shot by police officers. A device appeared to go off, we haven't confirmed that as of this time, we saw some smoke, may have heard a pop, haven't confirmed all that as of yet. There were three hostages, all of the hostages are safe and out of the building."
Earlier: A man previously convicted for protesting at Maryland buildings is holding hostages inside the Discovery Communications building in Silver Springs, Maryland. DCist reports that suspect James Jay Lee, 43, has "devices" strapped to his front and back. Lee, who has had issues with Discovery before, allegedly posted his demands online, saying he wants "new shows started by asking the public for inventive solution ideas to save the planet and the remaining wildlife on it." He adds, "The humans? The planet does not need humans."