FBI: 'Viable' Pipe Bomb Found on US Parade Route

WASHINGTON  – US officials are investigating a "viable" pipe bomb found in a backpack that was placed along a parade route in the western state of Washington, an FBI special agent told AFP on Tuesday.

The backpack had been placed along the route of a parade on Monday to celebrate Martin Luther King Day in the city of Spokane.

"Preliminary analysis reveal this was likely a viable device," agent Frank Harrill of the Federal Bureau of Investigation told AFP in an email.

Law enforcement sources described the device to ABC News as a "small pipe bomb" designed to be triggered by a radio frequency system.

They said it could have been intended to explode during the parade -- which was attended by some 1,500 people -- and appeared to have been designed to direct shrapnel in a particular direction.

"The march was rerouted after the suspicious backpack was detected by three workers in the area," Harrill said.

He added that authorities believe the device "was potentially lethal and could have had the ability to inflict multiple casualties."