4 Marines killed in shootout at US military site

Four US Marines have been killed by a gunman who opened fire at two military offices in Chattanooga, Tennessee, before being fatally shot in an attack officials called a brazen, brutal act of domestic terrorism.

The gunman, identified as 24-year-old Muhammad Youssef Abdulazeez, was shot dead after opening fire with a high-powered rifle at the pair of military facilities, which are seven miles apart, in Chattanooga, Tennessee.

Abdulazeez fired 25 to 30 rounds at the recruitment station, a US military official said. The doors were riddled with bullet holes. People within the premises fled through the back of the building.

Chattanooga police Officer Dennis Pedigo was shot in the ankle and taken to a hospital. A Marine recruiter was shot in the leg and was treated and released.

Abdulazeez was shot by the wounded police officer. Other officers also opened fire in the gun battle, police said.

The FBI said it was too early to speculate on a motive for the rampage, which comes at a time when US military and law enforcement authorities are increasingly concerned about the threat posed by 'lone wolves' to domestic targets.

"While it would be premature to speculate on the motives of the shooter at this time, we will conduct a thorough investigation of this tragedy and provide updates as they are available," the agency said in a statement.

Abdulazeez was a naturalized US citizen originally from Kuwait. He came to the United States in 1996 with his parents.

Authorities said Abdulazeez lived in the Chattanooga area recently, but reports indicate that he was from Phoenix, Arizona.

He was arrested on April 21 for driving under the influence in Hamilton County, Tennessee, according to the local news reports.

Police have not yet released a motive for why the gunman targeted the two military facilities and military personnel.

Officers working at one of the recruitment centres said they heard up to 50 shots fired. The glass door of the office, located in a strip mall, was riddled with bullet holes.

Witness Marilyn Hutcheson, who works at a glass company nearby, said she hard a barrage of gunfire.

She said: "It was rapid fire, like pow, pow, pow, pow, so quickly. The next thing I knew there were police cars coming from every direction."

"We're apprehensive. Not knowing what transpired, if it was a grievance or terrorist related, we just don't know. It's very scary."

Erica White, who witnessed the shooting from a hair salon next to the recruiting centre, told CNN: "We heard one pop, really loud pop. So we went to the door to see what it was.

"We saw a guy in a silver Mustang just unloading on the naval recruiting place."

The man then reloaded his gun and opened fire again, she said.

He then backed up his car, pulled up to another part of the recruiting centre and started shooting again.

President Barack Obama was briefed on the shooting by his national security team, the White House said.

Chattanooga Mayor Andy Berke said: "The suspect is down. Horrific incident in our community." 

Bill Killian, the US attorney for the eastern district of Tennessee, said the deadly incidents were being investigated as an "act of domestic terrorism". 

The FBI is now trying to determine if Abdulazeez has any ties to terror groups, if he was inspired by organizations like ISIS and if he had any accomplices.

The Justice Department said it is a “national security” investigation.