LAS VEGAS — Police officers were responding Wednesday to a “confirmed active shooter” in a building at the University of Nevada, Las Vegas, the university announced in a post on the social media platform X.

“This is not a test,” the university wrote. “RUN-HIDE-FIGHT.”

Las Vegas police said in a separate post on X that there appeared to be multiple victims.

The university said the shooter was at the Beam Hall, Frank and Estella Building, home of UNLV’s Lee Business School, which sits near the student union.

The shooting occurred in a city still scarred by one of the worst mass killings in U.S. history, the Oct. 1, 2017, mass shooting at the Mandalay Bay casino in Las Vegas, in which 60 were killed and hundreds more wounded.