Casino stocks moved lower in early trading Monday, Oct. 2, after a gunman opened fire on a crowd of people at a Las Vegas music festival, killing more than 50 and sending more than 400 to local hospitals.

The shooting occurred at the Mandalay Bay Hotel and Casino, owned by MGM Resorts Int'l (MGM) - Get Report . MGM stock traded down 5.52% Monday.

"Our hearts and prayers go out to the victims of last night's shooting, their families, and those still fighting for their lives," said Jim Murren, MGM's chairman and CEO, in a statement. "We are working with law enforcement and will continue to do all we can to help all of those involved."

At the same time, shares of Wynn Resorts, Ltd. (WYNN) - Get Report were down 1.24% and shares of Boyd Gaming Corp. (BYD) - Get Report were down 0.04%. Shares of Las Vegas Sands Corp. (LVS) - Get Report were up 1.26%.

The shooting occurred at the Route 91 Harvest music festival, which was happening across the street from the Mandalay Bay resort near McCarran International Airport on the south side of the Las Vegas Strip. Las Vegas police warned people not to head down the south end of the strip, where many casinos and hotels are located.

The massacre is the deadliest mass shooting in U.S. history. Officers found the suspect, identified as Stephen Paddock, 64 of Mesquite, Nevada, dead in a hotel room at the Mandalay Bay resort with over 10 firearms in the room.

Hotels nearby remained opened, but Mandalay Bay was closed early Monday.

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