Florida: A gunman has killed two people and wounded five others at a yoga studio in Florida's capital before killing himself, officials said.

Tallahassee Police Chief Michael DeLeo told reporters Friday night that the man shot six people and pistol-whipped another after walking into the studio, which is part of a small Tallahassee shopping centre.

The suspect then fatally shot himself, DeLeo said. Authorities have not identified the shooter or the victims. The conditions of the other victims are unclear.

DeLeo said police are asking for anyone who saw something unusual around the time of the shooting to contact police. He said the shooter acted alone and authorities are investigating possible motives. He declined to say what kind of gun the shooter had.

"We're all very saddened and shocked by the events that occurred, but it's important that people understand that there is no immediate threat outside of what has already occurred this evening," DeLeo said.

Melissa Hutchinson said she helped treat a "profusely" bleeding man who rushed into a bar after the incident. She said three people from the studio ran in, and they were told there was an active shooter.

"It was a shocking moment something happened like this," Hutchinson said.

The people who came in were injured, including the bleeding man who was pistol-whipped while trying to stop the shooter. They told her the shooter kept coming in and out of the studio. When he loaded his gun, people started pounding the windows of the studio to warn people.

City Commissioner Scott Maddox was on the scene. He said on Facebook, "In my public service career I have had to be on some bad scenes. This is the worst. Please pray."

Elle Welling said she was leaving a liquor store across the street from the shopping centre and saw at least three people loaded into ambulances.

"You don't think about this in Tallahassee and now you have to," said Welling, 26, who lives in the neighbourhood.

The plaza is home to popular restaurants, a jewellery store, a framing shop, a hair salon and other businesses.

Erskin Wesson, 64, said he was eating dinner with his family at a restaurant located below the yoga studio when they heard the gunshots above them.

"We just heard 'pow, pow, pow, pow,'" Wesson said. "It sounded like a limb falling on a tin roof and rolling." The restaurant's owner came by a short time later, asking if anyone was a doctor, Wesson said. His step-daughter is an emergency room nurse and helped paramedics for about an hour, he said.

Tallahassee Mayor Andrew Gillum, who is the Democratic nominee for governor, tweeted that he's breaking off the campaign trail to return to Tallahassee. He earlier appeared at a campaign event with former President Barack Obama.

"I'm deeply appreciative of law enforcement's quick response to the shooting at the yoga facility in Tallahassee today. No act of gun violence is acceptable. I'm in close communication with law enforcement officials and will be returning to Tallahassee tonight," Gillum tweeted.

Republican Gov. Rick Scott, who is challenging Democratic Senator Bill Nelson, called DeLeo and the head of the Florida Department of Law Enforcement to get details of the shooting.

"I will remain in constant communication with law enforcement. We have offered state assistance," Scott tweeted.

Tallahassee's crime and murder rate has been an issue in the governor's race, with Gillum's opponent, Republican former US Representative Ron DeSantis, calling the capital Florida's most crime-ridden city, a claim that is incorrect.