Timeline of terror in Chattanooga shootings

1 p.m.

* A woman who says she witnessed the shooting in Chattanooga says she heard a barrage of gunfire near one of the shooting sites. "It was rapid fire, like pow pow pow pow, so quickly. The next thing I knew there were police cars coming from every direction," said Marilyn Hutcheson, who works at a Binswanger Glass.

* Chattanooga Mayor Andy Berke said at a brief news conference that police were pursuing an active shooter and there was an officer down.

* A woman who says she witnessed a shooting in Chattanooga says she heard a barrage of gunfire near one of the shooting sites.

1:45 p.m.

* Shootings were reported at two locations in Chattanooga.

* One of them took place at the Armed Forces Career Center off Lee Highway. Television images of a door to the center in a strip mall showed more than a dozen bullet holes in the glass.

* About 7 miles away, another shooting happened at the Navy Operational Support Center and Marine Corps Reserve Center.

* Chattanooga police say the active shooter situation is over, but they have not said what happened to the suspect or suspects.

2 p.m.

* President Barack Obama has been briefed by his national security team on the shooting involving two military sites in Tennessee.

2:35 p.m.

* Tennessee Gov. Bill Haslam says people serving their country have lost their lives in the attacks on two military facilities there. Haslam did not say how many people were killed or provide further details about who was among the dead on Thursday.

2:50 p.m.

* The death toll in the Chattanooga shootings includes four U.S. Marines and the sole gunman believed responsible, a U.S. official told The Associated Press, speaking on condition of anonymity to discuss an ongoing investigation. The official said two others, a soldier and a police officer, were wounded.

3:10 p.m.

* A U.S. attorney says the killing of four people during a shooting rampage in Chattanooga is an "act of domestic terrorism."

3:30 p.m.

* The Chattanooga mayor says the killings of four military personnel during an attack on two facilities in the city are "incomprehensible."

4 p.m.

* A U.S. official says the gunman in the shootings in Tennessee has been identified as 24-year-old Mohammad Youssef Abdulazeez. He was believed to have been born in Kuwait, and it was unclear whether he was a U.S. or Kuwaiti citizen. The official was speaking on condition of anonymity to discuss the ongoing, sensitive investigation. He is from Hixson, which is just a few miles across the river from downtown Chattanooga.

4:40 p.m.

* Law enforcement swarmed the house believed to belong to the man authorities say killed four Marines and wounded others in the pair of attacks on local military facilities.

* An Associated Press reporter saw officers with weapons drawn at the house and two females were led away in handcuffs. It's not clear who those females are.

5:15 p.m.

* Vice President Joe Biden says the United States will get to the bottom of the shootings that killed at least four Marines in Chattanooga. Biden says the young Marines killed were part of what he's calling "probably the most incredible generation that this country has seen." He's pointing out that more than 4 million Americans have signed up for military service since 9/11, even though they knew they'd almost certainly be put in harm's way.

5:45 p.m.

* Democratic presidential candidate Hillary Rodham Clinton describes the shootings as "senseless violence" that she linked to other recent mass shootings. "It's terrible when we lose Marines anywhere in the world. But to lose four in Chattanooga, Tennessee, is just heartbreaking," she told reporters.

6:17 p.m.

* Navy Secretary Ray Mabus is expressing condolences for four Marines killed in shootings in Tennessee. He called the victims "four heroes." Mabus says "the tragedy in Chattanooga is both devastating and senseless."

6:27 p.m.

* The U.S. National Counterterrorism Center is reporting no apparent nexus to terrorism has been uncovered in the investigation of the fatal shootings in Tennessee, but intelligence officials are monitoring the investigation closely.

* It also says there has been no credible claim of responsibility so far for anyone who might have influenced the gunman, who also was killed.

* The center says there was no connection uncovered so far to terrorism. But it described efforts by the Islamic State group to revitalize homegrown extremists to conduct physical attacks inside the United States.

6:30 p.m.

* Attorney General Loretta Lynch says she's directing the FBI to take the lead on a "national security" investigation into the Chattanooga attacks. She said the two shootings at military sites in Chattanooga represented a "heinous attack."

7 p.m.

* A United States official says there's no indication that the suspected Chattanooga gunman was under investigation by the FBI or on the radar of federal law enforcement at the time of the shooting. The official was briefed on the investigation but was not authorized to discuss an ongoing investigation and spoke on condition of anonymity.

9:30 p.m.

* University of Tennessee at Chattanooga spokesman Mike Andrews said Moham-mad Youssef Abdulazeez graduated in 2012 with a bachelor's degree in electrical engineering.

* The Tennessee Valley Authority confirmed that he also was a student intern a few years ago at the authority, a federally owned utility that operates power plants and dams.

* Hussnain Javid, a 21-year-old senior at the university, said he and Abdulazeez studied electrical engineering at the same college and they both graduated from Red Bank High School near Chattanooga several years apart. Abdulazeez was on the high school's wrestling team and was a popular student. avid said Abdulazeez was "very outgoing" and that he was well-known.

11:10 p.m.

* U.S. Attorney Bill Killian says investigators do not believe that there are any threats to the general public following the fatal shooting of four marines at a recruiting center and another U.S. military site a few miles apart. Killian told a news conference Thursday night that the investigation into the shooting is "an ongoing extensive and expansive investigation with federal, state and local agencies, headed by the FBI. As far as we know, at this juncture there are no safety concerns for the general public," Killian said. Authorities also told the news conference that they still have not uncovered a motive for the shootings.

11:20 p.m.

* An FBI official says investigators have no evidence at this point that anyone but a lone gunman was involved in the fatal shooting of four marines in Tennessee.

* FBI agent Ed Reinhold also told a news conference Thursday night that the shooter initially fired from inside his car when he drove by a military recruiting center at a strip mall. Reinhold said the shooter then drove to another U.S. military site, where he got out of his car before fatally shooting the marines. Asked about potential accomplices, Reinhold responded, "There is no indication at this point that anybody else was involved. Obviously, we're still at the beginning of this investigation," he said. "We will explore any possibility and that includes whether or not anyone else was involved."