Police in two states are probing suspicious letters, several sent to hotels near MetLife Stadium, the site of Sunday's Super Bowl, and one sent to the New York office of Rudy Giuliani.
Several of the letters mailed to hotels in New Jersey contained white powder, though at least one was tested and determined to be harmless. Authorities believe that all the envelopes sent to hotels in New Jersey were mailed from the same source.
There are no reported injuries at this time, and the locations are being secured. The Joint Terrorism Task Force and Hazard Materials units have responded to several locations.
A federal law enforcement official said one of the envelopes contained baking soda.
New York City police likewise say preliminary tests showed no threat from white powder that was found in a letter sent to former New York City Mayor Rudolph Giuliani's company in Manhattan.
In New Jersey, the suspicious mailings went to at least five hotels, Carlstadt Police Detective John Cleary said.
The federal law enforcement official, who wasn't authorized to comment publicly and spoke on condition of anonymity, said powder from one envelope tested positive for baking soda. It's not clear where that letter was sent.
Hackensack University Medical Center received a number of people for evaluation because they came in contact with the letters, but a hospital spokeswoman said there were no reported illnesses or injuries.
The mailings arrived at an Econo Lodge in Carlstadt, a Homestead Inn in East Rutherford and a Renaissance Inn in Rutherford, Cleary said. Investigators intercepted additional envelopes from a mail truck before they reached a Holiday Inn Express and Hampton Inn in Carlstadt, he said.
Police were called to Giuliani's consulting firm near Rockefeller Center after a worker opened the suspicious letter addressed to Giuliani around 10:30 a.m. Friday, police said. Eight mailroom workers underwent decontamination as a precaution.
A representative for Giuliani's firm did not immediately respond to a comment request.
The Associated Press contributed to this report