An Air France flight from Paris to Detroit was forced to divert to Montreal on Wednesday due to U.S. flight restrictions linked to the Ebola outbreak in Central Africa after it was determined that one of the passengers was from the Democratic Republic of Congo, federal officials and the airline said.

Air France boarded the passenger "in error on a flight to the United States," a U.S. Customs and Border Protection spokesperson told CBS News in a statement. The spokesperson said that the passenger "should not have boarded the plane" because of "entry restrictions put in place to reduce the risk of the Ebola virus." CBP did not say when the person had last been in the Congo.

Air France said the flight was diverted "at the request of U.S. authorities" and said there was "no medical emergency on board." 

When reached about the incident, the Federal Aviation Administration directed CBS News to CBP. CBS News has also reached out to the U.S. Centers for Disease Control and Prevention for comment. 

According to the flight tracking website FlightAware, Air France Flight 378 from Paris-Charles de Gaulle International Airport landed at Montreal Trudeau International Airport at 5:15 p.m. ET. 

The current Ebola outbreak centered in eastern Congo was confirmed May 15 by the Africa Centres for Disease Control and Prevention. The World Health Organization said Wednesday there were at least 600 suspected Ebola cases so far, including 139 suspected deaths from the virus. Health officials say the outbreak is linked to the Bundibugyo strain, for which there are no approved vaccines or treatments.

Removed passenger showed no symptoms, Canada says  

The passenger was assessed by a Public Health Agency of Canada Quarantine Officer, the agency said in a statement. The officer determined that the passenger was asymptomatic. 

The passenger was then placed on a flight back to Paris, the agency said. 

Ebola can only spread if a person is showing symptoms, according to the CDC and CBS News medical correspondent Dr. Céline Gounder, an infectious diseases specialist who deployed to West Africa during a past Ebola outbreak.

"You cannot transmit Ebola, you cannot transmit it at all, if you do not have symptoms," Gounder told "CBS Mornings" on Thursday. 

"Should people be worried about this? No. You are not going to catch Ebola from sitting next to somebody who doesn't have symptoms on the plane," she said. 

Travel restrictions 

The CDC announced on May 18 that people without U.S. passports who had traveled to Congo, Uganda or South Sudan in the past three weeks would be restricted from entering the country. 

The Department of Homeland Security will require all U.S.-bound flights carrying foreign travelers who have been in Congo, Uganda or South Sudan at any point in the previous 21 days to fly into Washington-Dulles International Airport in Virginia, the agency said Wednesday. On Thursday, the State Department said all U.S. citizens and lawful permanent residents who had been in the Congo, Uganda or South Sudan before entering the U.S. must also only fly into Washington-Dulles. 

The CDC and DHS will "apply enhanced public health screening" at the airport, the State Department said. It's unclear how the DHS and State Department rules impact the CDC's earlier order.

Gounder said the decision to funnel passengers to one airport is "not dissimilar" to what officials did during the 2013-2016 Ebola outbreak in West Africa, when passengers from affected regions could only enter the U.S. through three designated airports. The system is not meant to "prevent flight or prevent passengers from coming here entirely," she said, but allows for health screenings. 

Gounder also noted pre-existing immigration restrictions meant "there wasn't much travel happening" between the affected countries and the U.S.

Passenger recounts confusion, concern 

Deborah Mistor, a business class passenger aboard the flight, told CBS News in an interview Wednesday night that the passenger disembarked from the back of the plane at Montreal Trudeau. The remaining passengers were then flown from Montreal to Detroit aboard the same aircraft, she said. 

Mistor said the passengers were notified by the captain about four hours before they were initially due to arrive in Detroit that U.S. authorities were not allowing the plane to land in the U.S. and the flight was being diverted. The captain did not provide a reason for why authorities were not letting the plane land, she said.

"I think enough people must have been questioning what was going on because 30 minutes later, he came back on and said that he wanted to confirm that there was nothing wrong with the plane, there were no technical difficulties, that it was strictly because of U.S. authorities not allowing us to land in the U.S.," Mistor told CBS News.

She said that flight attendants then put on face masks.

"They're telling you it's OK, it's not a mechanical issue, but everybody has a mask on," Mistor said.

Gounder said that since the passenger had no symptoms, the decision to mask was "really sending the wrong message." 

"That is going to be scaring people unnecessarily," she said.