The Rainbow Bridge connecting the U.S. and Canada at Niagara Falls, New York, has been closed after a vehicle explosion, according to the FBI and local authorities, Paralel.Az reports citing ABC News.

There are believed to be fatalities from the incident, multiple officials confirmed.

Investigators have found some sort of suitcase or briefcase on-scene, sources told ABC News. They are treating it as a possible explosive device as a precaution and the bomb squad is handling the package.

The Niagara Falls mayor's office said the incident involved a vehicle crossing into the U.S. from Canada.

The FBI is at the scene.

The White House is also monitoring the situation, a White House official said.