Two letters sent to New York Mayor Michael Bloomberg and the gun control group Mayors Against Illegal Guns this past weekend which tested positive for ricin were postmarked in Shreveport.

CNN is reporting that one letter was opened at the New York city government's mail facility, while the other letter was opened by the director of Mayors Against Illegal Guns, Mark Glaze. No fatalities have been reported, though some who handled the letter to Mayor Bloomberg reportedly showed temporary symptoms of ricin exposure.

Both were postmarked in Shreveport on May 20, according to the American Postal Workers Union.

"Further analysis is now being conducted in a specially-equipped laboratory," said the USPS said in a Mandatory Stand-Up Talk given to employees in the New York and Washington Districts on May 28 and 29. "In addition, law enforcement officials are in the process of searching to determine if there may be additional letters."

Bloomberg is a staunch advocate of gun control and co-founded the group Mayors Against Illegal Guns.

We'll have more info on this story as it develops.

[via CNN]