A female healthcare worker with Doctors Without Borders who was quarantined because she had contact with Ebola patients in Sierra Leone has developed a fever after arriving at Newark Liberty Airport, the New Jersey State Health Department said on Friday.

She has been isolated and is being evaluated at University Hospital in Newark. The woman was tested for Ebola on Friday, and results were expected on Saturday, WABC reported.

She had no symptoms upon arrival in Newark, but said she had contact with patients while in Sierra Leone when questioned at the airport, The Register reported. She was put under quarantine due to the possibility she was exposed to Ebola. The New York Times and WABC said that she had treated patients in the West African country.

She developed a fever while under quarantine later on Friday night, the New Jersey State Health Department said.

New Jersey Gov. Chris Christie said during a Friday news conference said that the woman, a U.S. citizen, was not a resident of New Jersey and was intending to go on to New York. Later Friday night, Doctors Without Borders confirmed that she was one of its health care workers, WNBC Managing Editor Steven Bognar reported.

Sources told WABC that the health care worker was on United Flight 969, which was reportedly isolated on the tarmac.

New Jersey Gov. Chris Christie and New York Gov. Andrew Cuomo ordered a mandatory, 21-day quarantine for all health care workers and other travelers who have had contact with Ebola victims in West Africa. Travelers from Ebola affected areas who are considered to be at lower risk of exposure were to be monitored for symptoms, CBS New York reported. The new Ebola screening procedure was announced the day after officials confirmed Dr. Craig Spencer had tested positive for Ebola, the first case of the disease in New York City and the fourth case in the U.S.

This is a developing story. Check back for updates.