Local police said all victims' conditions are stable, Xinhua reported.
The incident happened at the Power Ultra Lounge in Little Rock. The age of victims ranged from 16 to mid-20s.
The police said they believed it was not a terror-related incident and appeared to be a dispute. They are still investigating the mass shooting incident.
Taptejdeep Singh, who was a light rail operator at the Valley Transportation Authority (VTA) for nine years, was the first victim to be publicly identified by his family, The Mercury News reported.
Singh, born in India and raised in Union City, California, has left behind his wife, three-year-old son, one-year-old daughter, and a grieving Sikh community in the Sanfrancisco Bay Area, which described him as a "helpful and caring" man.
Co-workers at the light rail yard of the VTA hailed Singh as a hero, saying he left the safety of an office room, where some colleagues were hiding, to help others escape the line of fire.
Samuel Cassidy, 57, a maintenance worker of the VTA, San Jose, on Wednesday gunned down eight of his co-workers and critically injured another in a one of the deadliest shootings in California state this year.
As police arrived at the scene, the killer died of a self-inflicted gunshot.
The gunman who opened fire on coworkers bypassed certain people and so appeared to select those he shot, a witness said.
"He ... was targeting certain people. He walked by other people," Kirk Bertolet, a worker at the Santa Clara Valley VTA in San Jose, told CNN affiliate KGO on Wednesday night.
"He let other people live as he gunned down other people," Bertolet said.
The gunman, armed with two semi-automatic handguns, shot coworkers in two buildings around the time of a morning shift change before taking his own life in front of responding law enforcement officers, authorities said.
At least eight of the nine killed were VTA employees, and investigators are trying to determine the motive, officials said.
Singh worked at a separate building from where most of the other victims were found, giving the impression that Cassidy had selected his victims. Singh was fatally shot in the stairwell of a VTA building, the report said.
Singh's brother-in-law, P.J. Bath, another light rail operator at the VTA, confirmed that the shooter and Singh were in different buildings initially but said nothing on the victims being pre-decided by the killer.
"He just happened to be in the way, I guess. He was always helpful to everyone and caring," Bath said
"We are in very deep grief, Singh's uncle Sakhwant Dhillon told the San Jose-based newspaper.
"He told people, 'be careful, hide.' He was running around the building to save others' lives. He was a good person. He helped everybody," Dhillon said.
Singh's brother Bagga Singh said he was told that his brother had saved a lady when he "rushed down the stairway, where he was eventually shot.
Singh may be considered a hero, but "he should have saved his life, too. We lost a good person, Bagga said.
Emotional scenes were seen at the Red Cross Center in the city where families of the victims gathered after the incident was reported.
Singh's family, including his father, hugged and cried.
The other victims of the shooting were identified as Paul Delacruz Megia (42), Adrian Balleza (29), Jose Dejesus Hernandez (35), Timothy Michael Romo (49), Michael Joseph Rudometkin (40), Abdolvahab Alaghmandan (63), and Lars Kepler Lane (63). The eighth person who was killed was identified as Alex Ward Fritch (49).
Minutes after the incident, a fire was reported at Cassidy's home, about 13 kilometres from the VTA office.
The fire was extinguished in an hour-long operation. Police said a separate investigation is going on in the fire.
Cassidy, the identified gunman, resented his work, his ex-wife Cecilia Nelms told CNN affiliate the Bay Area News Group.
He often spoke angrily about his coworkers and bosses and at times directed his anger at her, Nelms told the outlet.
When the two were married, he "resented what he saw as unfair work assignments" and "would rant about his job when he got home," she said.
Meanwhile, President Joe Biden reacted to the latest shooting incident by urging Congress to "take immediate action" on gun legislation.
"Enough," he said on Wednesday. "Once again, I urge Congress to take immediate action and heed the call of the American people, including the vast majority of gun owners, to help end this epidemic of gun violence in America."
The shooting is the latest example of America's gun violence scourge. It is the 232nd mass shooting this year in the country, according to a tally by the Gun Violence Archive.
A 16-year-old girl died just after 1 a.m. on Sunday, shortly after gunfire broke out at the Bicentennial Park Amphitheater in Columbus, the capital city of Ohio, Xinhua news agency quoted the local police as saying.
Five other teens were injured in the shooting.
The incident occurred at a private event that was promoted on social media, according to the police statement.
What sparked the shooting remains unclear, and police have not identified a suspect, the NBC Columbus-affiliate WCMH reported.
In Youngstown, the ninth largest city in Ohio, three people were shot dead and five others injured at a bar on early Sunday morning, according to a CNN report, citing local police sources.
Police responded to the reports of shooting at the Torch Club Bar & Grille in Youngstown shortly after 2 a.m. on Sunday, said the report.
Detectives said some sort of argument broke out near the bar and there was "an exchange of gunfire", local media outlet WKBN reported.
Youngstown has witnessed 11 homicides this year, with 42 people shot and wounded, said WKBN.
In Bridgeton, New Jersey, two people were killed with 12 others injured in a house party shooting just before midnight, the authorities said on Sunday.
The dead were a 30-year-old man and a 25-year-old woman, state police said.
One of the injured, all adults, is in critical condition.
Troopers responded to the scene at 11.50 p.m. Saturday, the state police said.
More than a hundred people were at that home for a party at the time, according to an ABC News report.
In North Charleston, South Carolina, a 14-year-old girl was shot dead and another 14 people were injured after an unauthorised neighbourhood concert on Saturday evening, local media outlet WCIV reported on Sunday.
Authorities said the shooting occurred after a fight broke out near the concert stage. Police are investigating the incident.
In Minneapolis, Minnesota, two people died and another eight were injured in a shooting incident early Saturday morning.
The Minneapolis Police Department (MPD) said officers responded to "an exceptionally chaotic scene" at 1.59 a.m. at a bar in downtown Minneapolis.
Preliminary investigation revealed two people both pulled out guns and began shooting at each other as they got into a verbal confrontation.
"The two deceased are males. One male is in critical condition and the remaining 7 have non-life-threatening injuries," the MPD said in a statement.
Despite the frequency of multiple mass shootings across the US, major gun control legislation is unlikely due to deep partisan and cultural divide in the country, experts say.
According to Odessa Police Department, one shooter was killed and "the threat has been contained", Xinhua news agency reported on Saturday.
Odessa Police Department earlier sent a Facebook alert on the active shooting, saying "At this time there are multiple gunshot victims. The suspect just hijacked a US mail carrier truck." It also urged people to get off the road and "use extreme caution."
Odessa is about 30 km southwest of Midland, which is a city in western Texas. Part of the Permian Basin area, it is an oil industry centre.
Of those suffering gunshot wounds, at least one person remained in critical condition by 3 a.m. (local time) on Friday, Xinhua news agency quoted Indianapolis Metropolitan Police Department Spokesperson Genae Cook as saying at a news conference.
An unknown number of others went to local hospitals with injuries.
No law enforcement officers were among the wounded.
Cook said that the eight people were killed in and around the facility near the Indianapolis International Airport..
The shooter has taken his own life, Cook added.
This is the fourth mass shooting in Indianapolis this year, according to the Gun Violence Archive.
The FedEx hub employs more than 4,500 people and is the second-largest facility in the company’s global network, local media reported.