.22 caliber bullet found on Southwest Airlines plane as passengers boarded

(CBS/AP) PORTLAND, Ore. - A flight attendant found a .22-caliber bullet on the floor of a Southwest Airlines plane Friday morning as passengers were boarding for the flight from Portland, Ore. to Chicago.

A Port of Portland spokesman says passengers were taken off the plane to be re-screened by the TSA and the plane was searched, according to CBS affiliate KOIN.

Port spokesman Steve Johnson says all were cleared for the flight to take off.   

He said the flight was delayed for nearly two hours.

The port operates the Portland International Airport; authorities are still looking into how the bullet got on the aircraft.

A report from the port police agency said it was found near the front of the plane.