Activity at Seattle-Tacoma International Airport ceased for about 40 minutes last night after a man walked off during a security screening, according to the airport's Transportation Security Administration.

About 6:40 p.m., the man went through a central checkpoint and was selected for a secondary screening. Instead of waiting, he picked up his luggage and walked away.

Port of Seattle police tracked him down and questioned him, said TSA spokeswoman Jennifer Peppin.

Lt. John Hornbuckle said the situation appeared to be "a misunderstanding" and the man was rescreened and continued on his way.

In the meantime, passengers were not let out of the airport and could not get through security checks until about 7:20 p.m.