Chaos erupted outside Barclays Center in Downtown Brooklyn on Wednesday when an innocent bystander was shot in broad daylight after an argument between two men, police said.

The suspect — who remains at large — was arguing with another man near the Atlantic Center Mall on the corner of Atlantic and Flatbush avenues, across the street from Barclays Center, when he opened fire just after 2 p.m., striking a 50-year-old bystander in the ankle and sending people in the street running for cover, according to authorities. 

The man "brandished a firearm and fired several rounds," NYPD Deputy Chief Vincent DiDonato said during a news conference early Wednesday evening.

In surveillance video released by police, the suspect was seen walking on the sidewalk, turning around, firing the gun and then running across the street. Investigators also found a baseball hat and glasses believed to belong to the suspect, police said.

The victim was taken to NewYork-Presbyterian Brooklyn Methodist Hospital where he was last known to be in "good condition," according to DiDonato.

The suspect fled east on Atlantic Avenue, DiDonato said. Police were still searching for him Thursday morning. 

"He might have gone eastbound and then northbound on Fort Greene [Place]," DiDonato said.

Investigators believe the argument may have started near the Atlantic Avenue train station, according to DiDonato.

Danny Noel, 43, who manages the Mandee clothing store at the mall, said he saw people running from the scene.

"We heard gunshots. When we looked up, we saw someone with red shorts running past the window," he said. "We immediately locked the doors because we didn't know if he was going to run into the mall."

Noel said he ushered everyone in the store, including children, away from the windows and toward the back of the store in case of more shots.

"We just took the right precautions so that everyone in the store was safe," he said. "People were panicking."

Marc Klein, 37, of Kensington, said he was standing near a Starbucks and talking on his phone when he heard the gunshots. 

"I thought it was firecrackers. Next thing I know people are running for safety," he said. "I didn't want to be another victim."

Hot dog vendor Muhammad Alam, 47, said he heard about five or six shots and ran inside a P.C. Richard & Son.

"I heard the noise; a shooting," he said. "I saw one guy fall down. I saw one guy running ... I was nervous. A lot of people were scared and running."

The NYPD quickly deemed the incident to be unrelated to terrorism via a tweet from its official counterterrorism account.

"I'm going to say thank God that we only have one [victim] in light of what happened today in our country," DiDonato added. "Thank God we only had one individual hit. Thank God, it could have been a lot worse."

Earlier in the day, Rep. Steve Scalise and three other people were shot and injured during a congressional baseball practice in Alexandria, Virginia, near Washington, D.C. Meanwhile, a UPS driver opened fire at a package-sorting center in San Francisco, killing three people before fatally shooting himself, authorities said.