At least one person was killed and four others wounded in a shooting in Austin, Texas early Sunday, with police warning that the shooter was still at large.

The incident began shortly after 2:15am (0715 GMT) in a busy downtown area filled with bars and nightclubs, with police warning people on Twitter to steer clear of the area due to an "active shooter".

"Active shooter incident downtown, multiple victims. Stay away from downtown," Austin police tweeted.

One woman was killed and three other women were rushed to a local hospital with gunshot wounds, the Austin-Travis County Emergency Medical Services said.

A fifth victim, a man, refused aid, the ATCEMS said.

Police later confirmed there had been a second, separate shooting incident in the area, which took place just minutes later, although only the gunman was injured.

Police across the country, and especially in Texas, remain on edge after a rash of shooting incidents, including one on July 7 in Dallas which saw five officers shot dead by a black extremist as they were protecting a peaceful march against police brutality.

At the time, police initially thought they were facing multiple shooters. Instead, it turned out to be one individual armed with a rifle who was firing from different spots.

'Very chaotic scene'

At a pre-dawn press conference broadcast via Periscope, Austin Police Chief of Staff Brian Manley said the unidentified shooter in the first incident, believed to be a white or light-skinned Hispanic male in his 20s, was still at large.

After receiving first reports of the incident 2:17 am, officers arrived in the busy downtown area where they found "a very chaotic scene," Manley said.

There appeared to have been a disturbance during which an individual pulled out a gun and fired into a crowd of pedestrians, he said.

A woman in her 20s was shot and died at the scene.

Seven minutes later police were notified of a second shooting inside a nearby parking garage, he said.

In that incident, an individual pulled out a gun and fired, but was then confronted by witnesses who knocked him down and disarmed him.

Manley said the alleged shooter, who was injured, was apprehended and taken to hospital. His condition was not immediately clear.

It was unclear if the shooters knew any of their victims, with Manley saying it was part of the ongoing investigation.

He called for any witnesses with video footage or pictures to share their files with police.

Sam Vedamanikam, 26, told the Austin American-Statesman newspaper that he and several friends were leaving a dance club and heading to their car when they heard four or five gunshots.

"There were just tons of people on Sixth Street and I see all of them jump toward the ground," Vedamanikam told the newspaper. "A lot of people were screaming."

Witness Dorian Santiago described scenes of panic as people scrambled for safety when gunshots rang out.

"We heard five shots then people started running like crazy," Santiago told Sky News.