After spending the morning taking in the breathtaking sights at Niagara Falls, a group of tourists boarded a bus to return to New York City, not knowing about an hour later, their bus would be lying on its side in the ditch off the New York State Thruway.

"Avoid the NYS Thruway eastbound at all costs as a tour bus has rolled over near the Erie and Genesee County lines," Erie County executive Mark Poloncarz said on X. "This is a potential mass casualty incident," he said, adding that the county's emergency and security services are assisting.

Authorities say a tour bus returning to New York City from Niagara Falls has crashed on an interstate highway, killing five passengers and injuring many others.