FedEx Corp. confirmed that company “team members” were among those killed by a gunman who opened fire at FedEx Ground facility near the Indianapolis airport and then took his own life.

The shooting late Thursday left eight people killed and a least five hospitalized, including one victim with critical injuries, according to an Associated Press account of police statements. Authorities haven’t identified the shooter or said whether he was a FedEx worker, the AP said.

“We are deeply shocked and saddened by the loss of our team members following the tragic shooting,” FedEx said in a statement. “Our most heartfelt sympathies are with all those affected by this senseless act of violence.”

FedEx didn’t immediately confirm if the victims were direct employees or hired by contractors that deliver packages for the Memphis, Tennessee-based courier. The company said it is cooperating with the investigation.

The incident adds to a flare-up of recent mass shootings across the U.S., including 10 killed in a Boulder, Colorado, supermarket; eight gunned down at massage businesses in the Atlanta area; and a pregnant women among five people shot dead in January in Indianapolis, the AP said.