CNN is reporting hazardous materials teams and a bomb squad responded this morning after white powder was found at three hotels near the site of the Super Bowl, New Jersey authorities said.
In New York, authorities also were investigating the contents of a letter sent to the Manhattan office of former Mayor Rudy Giuliani, two law enforcement officials said.
The letter, opened in the mail room, contained white powder, according to law enforcement officials.
In New Jersey, the site of Sunday's Super Bowl, an unidentified substance was delivered to two hotels in Carlstadt and one in East Rutherford, said Jeanne Baratta, chief of staff at the Bergen County Executive's Office.
Law enforcement officials told CNN that six letters were discovered in New Jersey.
The FBI and local officials were monitoring the situation. Law enforcement officials said the incidents were considered a routine investigation, not a threat.