Chaos broke out at the main airport of Houston when a man fired gunshots into the air with his assault rifle, before shooting himself to death.
The incident took place on Thursday, when the suspect walking into the Terminal-B ticketing area of the Bush Intercontinental Airport, witnesses and law enforcement sources said.
Shortly after lunch time, the man started firing shots with his AR-15 rifle as he approached a security checkpoint.
He reportedly fired at least two shots before an air marshal fired at him, without injuring the gunman, after which he pulled out another gun and fatally shot himself.
"As he walked in he suddenly started shooting and every one got panic attack and started running helter-skelter," a traveler who witnessed the gunman shooting said.
"It seemed like quite a few shots. Everyone was scrambling, running left and right, turning tables up and hiding behind. Nobody knew what was happening. I couldn't tell where the shots were coming from," he said.
All terminals and flights were locked down as a result of the shooting.
The Federal Aviation Administration reported that many flights bound for BushAirport were held back at their departure airports.
The shooter was immediately rushed to a hospital where he was later pronounced dead.
Police have not made public the man's identity, though he is said to be around 30 years old.
"It is unclear if the unidentified man fatally shot himself or was killed by a Homeland Security agent who had confronted him," Houston police Captain Dwayne Ready said.
He said the agent confronted the gunman after the man fired one shot into the air and refused to drop his weapon.
The agent fired at the gunman at the same time as it appeared he was shooting himself, Ready said.
Officials say an autopsy of the gunman will be conducted on Friday.
According to the airport officials, while the terminal continues to be closed, remaining of the services in the airport are normally functioning.
Image: A police officers stands next to an unattended vehicle at Terminal B baggage claim level after a gunman opened fire at the terminal in George Bush Intercontinental Airport in Houston, Texas
Photograph: F Carter Smith/Reuters