CHATTANOOGA, Tenn., July 16 (UPI) -- A gunman opened fire at two U.S. military facilities in Chattanooga, Tenn., on Thursday, killing four Marines and seriously injuring three others, officials said. The suspected gunman was also killed.
The U.S. Navy, the Bureau of Alcohol, Tobacco and Firearms and the Department of Homeland Security are investigating the attack, which took place at a military recruiting center and ended at a Navy Reserve center less than six miles away.
The accused gunman, 24-year-old Mohammad Youssef Abdulazeez, is believed to be a naturalized U.S. citizen from Kuwait, the Washington Post reported, who emigrated with his family to the United States during the first Gulf War.
Abdulazeez was an electrical engineer who had grown up in Chattanooga with his conservative Muslim family, the Post report said. In April, he was arrested on suspicion of drunk driving, officials said.
"I am still trying to gather myself," Abdul Baasit, a Chattanooga imam said. "I am just blown away."
U.S. Attorney for the eastern district of Tennessee Bill Killian said law enforcement is investigating the incident "as an act of domestic terrorism." At a news conference Thursday afternoon, he said the FBI is now in charge of the investigation.
"The FBI and the other agencies are going to investigate this case thoroughly," Killian said. "They will determine after the facts are determined whether it's an act of terrorism at all, whether it's a crime and what the nature of that crime is, or whether it's a combination of those."
The incident began shortly before 11 a.m. EDT and by 1:15 p.m., the Chattanooga police tweeted that the "active shooter situation" was over. FBI agent Ed Reinhold said all the victims died at the reserve center.
Chattanooga Mayor Andy Berke said a number of people were shot and injured, including a Chattanooga police officer, who was shot in the ankle. He has been "treated very well" at Erlanger Health Center in the city. An officer told WCRB-TV in Chattanooga the injured officer was in stable condition.
The shootings prompted lockdowns across the region, including the governor's residence in Nashville, some 130 miles from Chattanooga. The War Memorial and the Tennessee Capitol complex also have additional security in place.
Chattanooga State Community College, local hospitals and offices were put on lockdown as the event went on. Some witnesses said they saw a person firing a high-powered rifle from a moving vehicle, possibly a convertible.
Berke called the shootings a "nightmare for the city of Chattanooga, one to which we will respond.
"It is incomprehensible to see what happened and the way that individuals who proudly serve our country were treated," he said. "As a city we will respond to this with every available resource that we have."
Reinhold would not explain why the FBI is investigating the incident as an act of terrorism. He said law enforcement had no advance knowledge of a possible attack.
U.S. President Barack Obama said he received a briefing on the situation from FBI Director James Comey. He said the White House has been in contact with the Defense Department to make sure all military facilities are being properly protected.
"Obviously when you have an attack on a U.S. military facility we have to make sure that we have all the information necessary to make an assessment of how this attack took place and how to take precautions in the future," he said. "We will be thorough and prompt in figuring out exactly what happened."
Obama also offered condolences to the families of the four Marines killed.
"It is a heartbreaking circumstance for these individuals, who have served our countries with great valor, to be killed in this fashion," he said.