LAS VEGAS: A gunman opened fire at a country music festival on the Las Vegas Strip on Sunday, killing at least 20 people and wounding more than 100 others before the suspect was killed by police.

Police described the suspect as being a local Las Vegas man who acted alone, Sheriff Joseph Lombardo of the Las Vegas Metropolitan Police Department said at a briefing. But authorities were seeking an Asian female who police described as a companion of the suspect, he said.

They said that rumours of other shootings in the area were false. Off-duty police were believe to be among the victims.

Witnesses on social media said the shooting broke out on the last night of the three-day Route 91 Harvest festival, a sold-out event attended by thousands and featuring top acts such as Eric Church, Sam Hunt and Jason Aldean.

US media, including Fox News, reported that Aldean was performing around 10:45 pm local time on Sunday when the rampage began but that he had been bundled safely off stage at the event outside the Mandalay Bay Resort and Casino in the Nevada gambling mecca. CNN reported all the artists were safe.

Las Vegas is an internationally renowned major resort city, known primarily for its gambling, shopping and entertainment.

Police have disclosed no information that would suggest a motive for the shooting or revealed the identify of the suspect.

Even so, the rampage was reminiscent of a mass shooting at a Paris rock concert in November 2015 that killed 89 people, part of a coordinated attack by Islamist militants that left 130 dead.