More than 50 people are now reported to have been killed and at least 200 injured in a mass shooting at a Las Vegas concert.

A gunman opened fire from the 32nd floor of the Mandalay Bay Hotel towards an open-air music festival being held close by.

Hundreds of people fled the scene and the sound of what appeared to be prolonged automatic gunfire could be heard on videos posted on social media.

Police responded to reports of an active shooter near the Mandalay Bay Hotel late on Sunday night local time.

A gunman opened fire at a country music festival being held on the Las Vegas strip.

Police reported clearing out the hotel’s 29th floor and working their way up to the 32nd floor.

A Twitter post from the Las Vegas Police Department described reports of an “active shooter” near or around the Mandalay Bay casino. The police later confirmed one shooter “was down” and said they were not looking for further suspects.

Videos on social media show hundreds of people fleeing from the scene of the Route 91 Harvest country music festival.

The sound of what appears to be automatic gunfire can be heard in some clips.

Las Vegas police advised people to avoid the area.

Some flights have resumed from Las Vegas McCarran airport after all were initially halted.

A tweet from the Las Vegas Convention and Visitors Bureau said: “We are all saddened by the events unfolding on the Strip. Our thoughts are with the victims, families and first responders.”

Earlier, the Foreign and Commonwealth Office updated its US travel advice to say: “We are in contact with the local authorities and urgently seeking further information following a shooting incident in Las Vegas around the Mandalay Bay Hotel, on the city’s main strip.

“A police operation is ongoing. You should avoid the area and follow the advice of the local security authorities.

“Road closures in the area have been reported, and some flights to McCarran International airport have been diverted.”