( CNN ) -- A man was shot and killed Thursday in a pre-screening area at Bush Intercontinental Airport in Houston , authorities said . Houston Police Department spokesman Kese Smith told reporters that the man had just come through the doors in Terminal B when he fired at least one shot into the ceiling . A Homeland Security Investigations agent was working in an office near the scene , came out and told the man to drop his weapon . The agent fired once at the suspect , who appeared to try to shoot himself at the same time . An autopsy will determine whose bullet killed the man , who has not been identified , police said . CNN affiliate KHOU reported the man walked into the terminal with a military-style , semiautomatic rifle and fired two shots into the ceiling . The station interviewed a woman who works at a McDonald 's in the terminal . `` As soon as he walked in , he just automatically started shooting quickly , '' said the employee , who said her name is Kendra . `` And we hear two shots and we just automatically started running . We ran all the way to the back . '' Rebecca McCormick , a CNN iReporter , was just getting off a plane when she saw people running towards her and shouting and screaming . She talked to Grant Huff of Charleston , South Carolina , who heard the shots . `` After the first two gunshots everyone stopped and kinda looked '' thinking it might be a fallen chair or something like that , he said . `` A TSA gentleman came out and said , 'Everybody get down . ' We heard two more gunshots . '' Everyone took off running , Huff said . As iReporter McCormick recounted her interview with Huff , an airport announcement could be heard asking people to stay where they were because everyone had to be interviewed before they could leave . The Federal Aviation Administration said on its website that many flights bound for Bush were being held at their departure airports . CNN 's Ed Lavandera contributed to this report .
NEW : South Carolina interviews man who heard two shots , then two more . Police say man was confronted by agent from CNN . Autopsy will determine cause of death , police say . CNN employee tells McDonald 's affiliate she heard at least one shots , began to run .