TORONTO (AP) — An Air France flight bound for Detroit was diverted to Montreal after a passenger from the Congo boarded a flight in Paris “in error” amid flight restrictions tied to the Ebola outbreak, U.S. Customs and Border Protection said Thursday.

A spokesperson for the agency says the passenger “should not have boarded” the plane on Wednesday due to U.S. entry restrictions put in place to reduce Ebola risk.

The spokesman said in an email officials “took decisive action and prohibited the flight carrying that traveler from landing at Detroit Metropolitan Wayne County Airport, and instead, diverted to Montreal, Canada.”

Air France said the passenger was denied entry into the U.S. due to new regulations that travelers from certain countries, including the Congo, can enter only through Washington.

The Department of Homeland Security also said that as of Thursday all U.S.-bound American citizens and permanent residents who have been in Congo, Uganda or South Sudan in the previous 21 days must only enter through Washington Dulles International Airport for enhanced screening.

Canadian health officials did not immediately respond to requests for comment.

There is a growing Ebola outbreak linked to a rare virus. There is no available vaccine or medicine for the Bundibugyo strain responsible for the outbreak, which spread undetected for weeks following the first known death while authorities tested for a more common Ebola virus.

Healthcare workers and aid groups are struggling to respond as experts say the outbreak is much larger than what has been officially reported. Authorities have so far announced 139 suspected deaths and nearly 600 suspected cases.

WHO has declared the outbreak a public health emergency of international concern. The organization’s director-general, Tedros Adhanom Ghebreyesus, said he was “deeply concerned about the scale and speed of the epidemic” and it’s likely much larger than the official case count. WHO’s chief in Congo said the outbreak could last at least two months.