Three people were killed and another critically injured in a shooting at a Las Vegas university on Wednesday, police said, with the suspect also dead.

The incident at the University of Nevada, Las Vegas, a short distance from the gambling hub's tourist-packed Las Vegas Strip, was the latest in the United States, where gun violence is a part of the fabric of daily life.

"According to our investigators at the scene, we have three deceased victims and one additional victim in critical condition at a local hospital," the Las Vegas Metropolitan Police Department wrote on social media.

"The suspect in this #ActiveShooter incident is also deceased."

Police said they had responded to calls around midday (2000 GMT) and indicated that officers had engaged a suspect on the campus, where gunshots rang out in at least two locations.

Television footage showed police military-style vehicles moving near containment lines, as well as dozens of young people being escorted through them.

One woman told local broadcaster KVVU that she had heard a series of loud noises and fled into a building on the campus, from which she was later evacuated by police.

"I was just having breakfast and then I heard three, like, loud booms," she told the station.

"Then two more, and then police showed up there and ran inside… but then after two minutes boom, boom, boom, more shots. So I ran into a basement, and then we were in the basement for 20 minutes."

Three hours after the shooting erupted, the university continued to urge people to shelter in place, saying that police were working to clear each building in turn and that the investigation remained ongoing.

"Law enforcement will potentially be coming to your door, follow directions, and exit calmly with your hands plainly seen," the university said.

Brett Forrest, a reporter from local outlet KSNV, told CNN he had been on the campus for an assignment and was continuing to shelter in place with dozens of students and faculty as they awaited the all-clear from police.

"We are told that they're coming building by building, slowly letting out each building making sure no additional victims or anyone else inside, so they might take a while," he said.

Universities in the area were shuttered for the rest of the day and flights into the nearby international airport were halted, the Federal Aviation Administration said.

Las Vegas is a gambling and entertainment hub that attracts millions of visitors every year, many of whom come to see large, high-profile events.

Last month, the city played host to its inaugural Formula One Grand Prix, and in February it will be the scene of the Super Bowl, the showcase final of the professional American football season.

The city was also the scene of one of America's deadliest-ever mass shootings, when a gunman opened fire on a crowded music festival in 2017, killing 60 people.

Mass shootings are alarmingly common in the United States, a country where there are more guns than people and where attempts to clamp down on their spread are always met with stiff resistance.

The country has recorded over 600 mass shootings this year, according to the Gun Violence Archive, a nongovernmental organization that defines a mass shooting as four or more people wounded or killed.

The Washington Post, which keeps its own tally of mass shootings, said that as of Monday, there had been 38 such incidents in which at least four people had been killed.

Efforts to tighten gun controls have for years run up against opposition from Republicans, staunch defenders of what they interpret as an unfettered constitutional right to weaponry.

The political paralysis endures despite widespread outrage over recurrent shootings.