Update 12:30 p.m. The NYPD sent out this tweet:
NYPD Bomb Squad determined suspicious package was a grenade-like novelty item mounted on a plaque with a sign: "Complaint Dept. Pull Pin."— NYPD NEWS (@NYPDnews) April 12, 2012
Update: 12:20 p.m. Whew. According to WNBC news, the "grenade" in question appears to be a "novelty grenade," and the all-clear has been given.
A suspicious package has been found at 2 World Financial Center. The New York Daily News' Rocco Parascandola and Joe Kemp report that a Fed Ex package was scanned that appeared to contain what looked like grenade.
Business Insider has an aerial photo of the crowd outside, while My Fox News has a live helicopter feed from above the lower Manhattan office. Twitter user Salvador Mendoza tweeted this picture of the on-the-ground evacuation:
We'll keep this post updated as more information comes in.