Baghdad, Iraq (CNN) -- U.S. troops shot and killed an Iraqi man at Baghdad International Airport on Sunday morning, a U.S. military spokesman said.
A military convoy attempted to stop the man, who they spotted driving a vehicle at high speed on an airport road, Col. Barry Johnson said.
"The vehicle was perceived as a threat and a decision was made to engage it with small-arms fire in order to stop it and to protect the convoy from a possible attack," Johnson said.
The driver did not respond to U.S. hand signals before troops opened fire, he said.
Baghdad police said the man was an engineer working at the airport. They did not name him.
"We deeply regret that this action resulted in the death of an Iraqi who was driving the vehicle," Johnson said.
Authorities are investigating the incident, he said.
Also Sunday, one person was killed and seven people were wounded in three separate car bombings in the Iraqi capital.
CNN's Mohammed Tawfeeq in Baghdad contributed to this report.