The gunman is also confirmed dead, according to authorities. No names of the deceased were released nor was a possible motive disclosed during a press conference Thursday afternoon. However, they do believe he was local resident who had several weapons on him but no body armor.

“Today is a nightmare for the city of Chattanooga,” Mayor Andy Berke said.

The rampage, which occurred within a 30-minute span, forced at least one hospital and two nearby colleges to lockdown. A mall in Cleveland, roughly 30 miles north of Chattanooga, was locked down as well because it also contained a recruiting center. Chattanooga State Community College, located near the second attack, announced Thursday afternoon it would close for the rest of the day in light of the day’s events and would reopen Friday.

The U.S. Department of Homeland Security activated a strike team for the local area, and in the state capitol of Nashville about 130 miles northwest, the governor’s residence was temporarily closed and additional security was placed at the State Capitol.

After the shooter hit his first target on Lee Highway around 10:45 a.m. Eastern time, he went to another recruiting center on Amnicola Highway, while being pursued by law enforcement, and opened fire.

All four killed were at the second site. A police officer was shot in the ankle and is reported to be in stable condition. Two other people were reported injured, although their condition was uncertain as of Thursday afternoon.

Roughly two-and-a-half hours after the incident began, police officers announced the active shooter situation was over.

Berke told reporters at a press conference that the city would respond with all the resources they have available. Chattanooga also will get assistance from federal officials as well.

“We are treating this as an act of domestic terrorism,” said U.S. Attorney William C. Killian, who represents the Eastern District of Tennessee.

However, Ed Reinhold, a special agent with the Federal Bureau of Investigation, said at the press conference that the agency had not yet determined whether it was a terrorist act or only a criminal one.

Still, Tennessee leaders were mourning as a result.

“I am heartbroken by the tragic shootings that have taken place today in my hometown,” said Tennessee U.S. Sen. Bob Corker, a former Chattanooga mayor. “We have been in touch with federal, state and local officials and continue to monitor developments and have offered our assistance. This is a difficult day for Tennesseans and our thoughts and prayers are with all affected by this tragedy.”

Tennessee Gov. Bill Haslam said via Twitter: “We’ve had a tragedy unfold in Chattanooga today. I know Tennesseans join me in being sickened and saddened by this senseless act.”

President Obama was briefed on the situation by national security officials, according to the White House.