A new alert has been issued to people travelling to, or currently in, parts of the USA and Canada.
The Foreign Office frequently updates its advice in a bid to keep people safe when travelling abroad and on Wednesday evening (November 22), a new warning was issued for people visiting parts of North America.
It comes after two people were killed by a speeding car that raced towards a US-Canada bridge from the American side crashed and exploded at a checkpoint in Niagara Falls on Wednesday. The incident prompted multiple borders to be closed for hours.
Authorities were not sure what spurred the wreck but said there were no signs it was a terror attack. The FBI's Buffalo office said late on Wednesday that it had concluded its investigation: "A search of the scene revealed no explosive materials, and no terrorism nexus was identified," it said in a statement.
"The matter has been turned over to the Niagara Falls Police Department as a traffic investigation."
Much remained unclear about the incident at the Rainbow Bridge, which prompted concerns on both sides of the border as the US headed into the Thanksgiving holiday.
Both US President Joe Biden and Canadian Prime Minister Justin Trudeau were briefed soon afterwards, and Mr Trudeau excused himself from a question period in the House of Commons to get further information, saying officials were "taking this extraordinarily seriously."
Security camera video released by the US government showed the car race through an intersection on a wet road, hit a low median and vaulted high into the air in a US Customs and Border Protection area just east of the main vehicle checkpoint.
The car flew for yards, twisting, and then crashed into a line of booths out of the camera's view.
The identities of those in the car were not released. Ms Hochul said it was unclear whether the driver, a western New York resident, was intentionally heading for the bridge that crosses the Niagara River.
The two people who died were a husband and wife, according to a person briefed on the investigation who spoke to The Associated Press on condition of anonymity because they were not authorised to release information about the people who were killed.
Matthew Miraglia, the FBI special agent in charge in Buffalo, said investigators had found no "derogatory" information on the driver. He added: "We're scanning his social media. There's nothing there".
A new alert on Gov.uk reads: "We are aware of reports of an explosion at the Rainbow Bridge border crossing between the US and Canada. Ports of entry between the US and Canada may be closed and there may be long delays. You should follow advice of the local authorities."
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