Police investigate 'security concern' involving 2 planes at Sea-Tac Airport (VIDEO)

SEATAC, Wash. --  Two planes were evacuated on arrival Sunday at Seattle-Tacoma International Airport due to what a spokesman called a "security concern."

Airport spokesman Perry Cooper identified the first plane as JetBlue flight 1006 from Long Beach which landed at 4:15 p.m.

Police were also investigating Skywest flight 4741 from Phoenix which landed safely at 4:36 p.m.

Cooper said that out of an abundance of caution, passengers were bused to their gates from the airport's third runway.

Both planes were cleared of any threat and allowed to return to their gates around 6:00 p.m.

Authorities said the investigation is ongoing. No further information was released.

Additionally, a Delta Air Lines spokesman says a flight from Los Angeles to Orlando was diverted to Dallas Sunday afternoon due to "a security concern."

Spokesman Morgan Durrant did not give specifics about the nature of the concern on Flight 1061, saying the company would defer to authorities on providing further details. He says passengers exited the Boeing 737-900, which was being examined by authorities.

Stay with Q13 FOX News for updates on this developing story.