Four Marines were killed Thursday in shootings at a pair of military facilities in Tennessee by a gunman who is being investigated for possible ties to Islamist terrorist groups, U.S. law enforcement officials said.

The shooter, identified by the FBI as Mohammad Youssef Abdul­azeez, 24, of Hixson, Tenn., was killed, apparently by police, at the end of a rampage that also wounded a Chattanooga police officer and a member of the U.S. military.

The assault marks the latest eruption of gun violence in the United States. It comes amid a flurry of recent arrests, disrupted plots and warnings from U.S. counterterrorism officials that the Islamic State terrorist group has called on its followers to mount attacks against U.S. targets, including military installations.

In brief remarks Thursday evening at the White House, President Obama described the Marines’ deaths as a “heartbreaking circumstance for these individuals who have served our country with great valor.”


He avoided describing the attack as a terrorist plot, saying that “we don’t know yet all the details” and that “a full investigation is taking place.” Even so, Obama described stepped-up security measures as White House officials urged the Pentagon to “make sure that all our defense facilities are properly attentive and vigilant as we sort through what happened.”

U.S. officials said an initial check of federal terrorism databases found no sign that Abdulazeez was under investigation. A senior U.S. law enforcement official confirmed that Abdulazeez’s father was investigated by the FBI several years ago and put on the terrorism watch list but was later removed.

The names of the Marines killed in the attack were not publicly disclosed Thursday as U.S. military officials sought to reach members of their families. A military official, speaking on the condition of anonymity because he was not authorized to discuss the case, said at least three of the Marines were from an artillery unit.

The 6th Marine Corps Recruiting District, which includes Tennessee, has closed all facilities within 40 miles of the shooting as a security measure.

Ray Mabus, secretary of the Navy, said in a statement that “while we expect our sailors and Marines to go into harm’s way, and they do so without hesi­ta­tion, an attack at home, in our community, is insidious and unfathomable.”

Authorities said they had reached no conclusions about the shooter’s motivations. He had recently been arrested for driving under the influence and appears to have made frequent postings online about his religious views.

In one Internet posting earlier this month, Abdulazeez had written “This life is a test of faith,” according to the SITE Intelligence Group, which monitors online postings by radical Islamist organizations and described the statement as an “aspiration for paradise.”

Even so, friends who said they had been in recent contact with Abdulazeez said they saw no indication that he was violent.

Hussnain Javid, a student at the University of Tennessee at Chattanooga, said that he was friendly with Abdulazeez and that they had both studied engineering.

Javid said that he ran into Abdulazeez about seven months ago at the Islamic Society of Greater Chattanooga and that Abdulazeez had recently moved back to the area and was looking for a job.

“Everything seemed fine,” Javid said. “It is very shocking. He seemed to be a very nice young man.”

The son of Kuwaiti and Palestinian parents, Abdulazeez was born in Kuwait but was a naturalized U.S. citizen, according to the accounts of friends and relatives.

He grew up in the Chattanooga area, where he was on the wrestling team at Red Bank High School. Beneath what appears to be his senior photo in the school’s yearbook is a provocative quote: “My name causes national security alerts. What does yours do?”

Public records indicate that he had no criminal history aside from vehicle-related offenses, including the arrest in April.

He appears to have participated in mixed martial arts and is in a fight video on YouTube. An online résumé indicates that Abdulazeez had recently worked as a “procurement engineer” with Global Trade Express.

In a news conference in Chattanooga, Edward Reinhold, the special agent in charge for the FBI in Knoxville, declined to discuss details of the investigation. A senior U.S. law enforcement official said it appeared that police killed Abdul­azeez as he fled.

“We will treat this as a terrorism investigation until it can be determined it was not,” he said.

In the neighborhood where Abdulazeez lived, news footage late Thursday showed heavily armed law enforcement officers entering the family home and taking away at least one handcuffed woman in traditional Muslim garb.

Elijah Wilkerson has lived in the neighborhood five years and said his wife often went walking with the Abdulazeezes.

“It’s like a family down there,” Wilkerson said, gesturing to his street.

Dean McDaniel, 59, is a longtime neighbor of the Abdulazeez family, said he regularly saw Abdulazeez and his siblings around the neighborhood.

“He was a good kid,” McDaniel says. “I trusted him in my home.”

The attack began at 10:45 a.m. when Abdulazeez fired rounds into the windows and door of a local military recruiting office. He then fled in a silver-colored Ford Mustang and drove to a Navy Reserve center several miles away, where he again opened fire and all five fatalities occurred.

Police in Chattanooga said shortly after 1:15 p.m. that the shooting was over and that the gunman was dead. Agents from the FBI as well as the Bureau of Alcohol, Tobacco, Firearms and Explosives converged on crime scenes littered with shattered glass.

Obama was briefed by his national security staff, White House spokesman Eric Schultz said Thursday afternoon. Public officials from Tennessee spent much of the afternoon gathering updates on the attack and issuing statements.

“I know the whole rest of the state joins me in just a feeling of being sick in our stomach for the lives lost and the senselessness of this,” said Gov. Bill Haslam (R).

The attack came almost exactly a month after a shooting at a historically black church in Charleston, S.C., that prompted debate not only over the Confederate flag but also over whether the terrorism label should be applied to the assault by a gunman allegedly motivated by racist views.

The shootings in Tennessee add to the mounting toll of gun violence in the United States but are more likely to be seen as part of a growing danger attributed to the influence of the Islamic State and other terrorist groups.

FBI Director James B. Comey recently disclosed that authorities had arrested more than 10 people over the past two months as part of a burst of activity by law enforcement officials to prevent attacks timed to the Fourth of July holiday as well as the Muslim observance of Ramadan.

Thursday’s attacks fell on the last day of the Muslim holy month.

Gibbons-Neff reported from Chattanooga, Goldman and Miller from Washington. Cari Gervin in Chattanooga and Mark Berman, Sari Horwitz, Carol D. Leonnig, Carol Morello, Jennifer Jenkins, Julie Tate and Alice Crites in Washington contributed to this report.