Buffalo Niagara International Airport is "open and fully operational" after it was reported to have shut down briefly following a vehicle explosion at the Rainbow Bridge in Niagara Falls Wednesday afternoon.

The U.S. Federal Aviation Administration reported shortly after 3 p.m. ET that a closure was in effect at the airport and that flights in and out of the airport were grounded.

However, airport officials never reported that the airport had closed, and stated in a pair of posts on X – formerly known as Twitter – shortly after 1:45 p.m. and 4 p.m. that the airport was "open and fully operational."

The explosion took place just after 1 p.m. on the U.S. side of the crossing, according to the U.S. Federal Bureau of Investigation’s (FBI) Buffalo field office.

"In response to the incident that is unfolding at the Rainbow Bridge, the NFTA is increasing security system-wide," the Niagara Frontier Transportation Authority wrote in an update posted to X on Wednesday afternoon, adding that cars coming into the Buffalo Airport will undergo security checks and travellers can expect additional screenings.

"We advise travellers to give themselves time for these extra precautions in addition to holiday travel." 

While Canadian government officials had been operating under the assumption that the explosion was terror-related, according to national security sources, U.S. officials now say there is "no indication of a terrorist attack" at this time.

According to multiple reports, two individuals believed to be in the vehicle have been pronounced dead.

With files from CTVNews.ca Senior Digital Parliamentary Reporter Rachel Aiello and CTV News Toronto Multi-Platform Writer Abby O'Brien

Correction:

An earlier version of this story stated that the Buffalo Niagara Airport had shut down temporarily after the FAA reported that there was a "closure" at the airport, however the airport clarified in a later statement that the airport had been "open and fully operational."