Updated 11.48am

One woman was killed and three people were hospitalised with bullet wounds in overnight shooting incidents in the Texas capital of Austin, USA, emergency officials said on social media early today.

Austin police said in a message on Twitter there had been "separate shootings within the same area" of the city's downtown, adding: "Both scenes are secure at this time."

The Austin-Travis County Emergency Medical Services agency said on Twitter that one woman had been killed and two other women and one man taken to hospital with gunshot wounds.

A fourth person was also hurt but declined medical treatment, according to the social media post from the agency.

An Austin police representative declined in an email to immediately provide further details.

The shootings follow several major acts of gun violence in the United States over the past several weeks.

On June 12, a gunman who sympathised with Islamist extremist groups killed 49 people at a nightclub in Orlando, Florida, in the deadliest mass shooting in modern US history.

On July 7, a US military veteran shot and killed five police officers in Dallas in the deadliest day for U.S. law enforcement since the September 11, 2001, attacks. Just over a week later another gunman killed three officers in Baton Rouge, Louisiana. Both attackers were killed by police.

Austin has a population of more than 900,000.