All passengers are being advised to shelter in place whilst police attend the scene.
San Antonio Police Department confirmed there was an officer involved shooting but insist there is no threat to the public.
They tweeted: “There is a confirmed officer involved shooting at 9800 Airport Blvd.
“There is no active threat to the public.
“As a precaution, the Airport has been put on lock down.
“No other injuries are reported.”
Passengers took to social media to express their shock.
On Twitter Sports reporter Sanjay Kirpalani said: “Just had to evacuate from San Antonio airport because of an active shooter inside.
“Heart is still racing, but glad to be safe for the moment.
“Make sure you tell your loved ones that you love them.”
More to follow…