Update 12:30 p.m.  The NYPD sent out this tweet: 

Which means that something like this

 

 

Or this, or this... Led to the evacuation of hundreds of people. 

 

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. 

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.