One suspect is in police custody and all departures were delayed after a passenger made a “direct threat” to the safety of an Alaska Airlines aircraft Saturday at Seattle-Tacoma International Airport (SEA).

Alaska Airlines confirmed to Fox News Digital there was a security incident at about 1 p.m. involving Alaska Airlines Flight 2123, operated by Horizon Air from Seattle to Walla Walla, Washington. 

“During taxi to the runway, a guest made a direct threat to the safety of the aircraft to one of our flight attendants,” a spokesperson said. “Our crew members followed their procedures and secured the aircraft on a runway away from the airport.”

There were 68 passengers and four crew members onboard, according to Alaska Airlines. 

Passengers were safely deplaned and will be returned to the terminal after a security screening, according to the Port of Seattle.

The aircraft will be subject to security measures before continuing, Alaska Airlines said.