Shots were fired at Houston's Bush Intercontinental Airport earlier today and an armed man was taken to an area hospital with life-threatening injuries.
A county forensics investigator said later that the man had died.
Reports said that the man attempted to go through a security checkpoint with a gun and authorities tried to apprehend him.
The unidentified man is said to have walked into the terminal with a military-style semi-automatic rifle and fired two shots into the ceiling. When confronted by an air marshal, he pulled out another gun and shot himself.
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"As soon as he walked in, he just automatically started shooting quickly," Kendra, a McDonald's employee working in the terminal at the time of the shooting, told Houston's KHOU. "And we hear two shots and we just automatically started running. We ran all the way to the back."
The Federal Aviation Administration (FAA) issued a ground stop for all flights at the city's largest international airport after the shots were fired. All of Terminal B was also closed.
According to Houston police spokesman John Cannon, a call saying there had been a "discharge of firearms" near the ticket counter at Terminal B came in at 1:35 p.m. on Thursday.
Police said they considered the shooting an isolated incident and were not searching for any other suspects.