(RNN) - The possibility of explosives and the presence of suspicious devices caused a worldwide security scare Friday as planes in two states and in London were searched.
Authorities searched a UPS cargo planes that landed at Newark Liberty International Airport in Newark, NJ, and two planes at Philadelphia International Airport in Philadelphia, PA.
"Out of an abundance of caution the planes were moved to a remote location where they are being met by law enforcement officials and swept," said UPS spokeswoman Jackie Blair in a statement.
Officials said a "manipulated" toner cartridge also was found on a cargo plane that landed in London on a flight originating in Yemen and bound for Chicago. However, tests for explosive materials were negative.
Suspicious activity also was reported in two more states. Law enforcement officials in Brooklyn, NY at New York State's Metro Tech Business Center investigated a suspicious UPS truck near a bridge.
No explosive devices were found.
In Portland, ME, a suspicious package was reported at a federal courthouse. The item turned out to be a backpack that had been placed at the entrance of the courthouse, said John Clark, chief deputy with the U.S. Marshall Service in Portland.
Clark said there is no indication the backpack is related to any of the other packages found on the planes, but that it was being investigated with an "abundance of caution" by the Portland Police office.
Clarke noted that incidents like this one have happened several times this year. "They are not unprecedented," he said.
A person who answered the phone at the FBI offices in New York declined to comment.
Media reports suggest that the plane that landed in London may have triggered the searches of the three planes in the U.S.