The usually busy Rainbow Bridge border crossing between Canada and the United States remains closed for the second day following a deadly car explosion on Wednesday.

Two people were killed in the explosion that occurred on the U.S. side of the crossing connecting Ontario and New York state before 11:30 a.m. yesterday.

According to officials, a speeding car headed toward a border checkpoint before leaving the road, crossing medians, and taking flight.

The incident was initially treated as a terrorist attack, but officials have since said they are treating it as a traffic accident.

New York Governor Kathy Hochul described the surveillance footage released of the incident as "surreal."

Ontario Premier Doug Ford said that provincial law enforcement authorities are "actively engaged" in assessing the situation and are working with U.S. officials as required.

The deadly incident led to the closure of all four border crossings in the Niagara area on the eve of the busy U.S. Thanksgiving holiday. About 6,000 vehicles cross the Rainbow Bridge each day, according to U.S. figures. But this number was 11,933 — nearly double — last year on Thanksgiving.

The Peace Bridge, Lewiston-Queenston, and Whirlpool bridges have reopened.