The blast is believed to have happened at a checkpoint on the Rainbow Bridge in Niagara Falls.

Images and video purportedly from the border control scene showed a fire and what was thought to be debris on the ground.

A security booth was singed by flames.

The governor of New York state also confirmed there had been an incident on the bridge - and authorities are closely monitoring the situation.

In a statement, Governor Kathy Hochul said: "I've been briefed on the incident on the Rainbow Bridge in Niagara Falls and we are closely monitoring the situation.

"State agencies are on site and ready to assist."

The bridge connects the two countries across the Niagara River.

The Niagara Falls Bridge Commission reports all four border crossings connecting Ontario in Canada to western New York have been closed.

They are the Rainbow, Lewiston, Whirlpool and Peace Bridges.

In a statement on X, the FBI in Buffalo wrote: "The FBI Buffalo field office is investigating a vehicle explosion at the Rainbow Bridge, a border crossing between the US and Canada in Niagara Falls.

"The FBI is coordinating with our local, state and federal law enforcement partners in this investigation. As this situation is very fluid, that's all we can say at this time."

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