A female healthcare worker 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.

She had no symptoms upon arrival in Newark, but was put under quarantine due to the possibility she was exposed to Ebola. The woman said she had contact with patients while in Sierra Leone when questioned at the airport, The Register reported.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 that a legal quarantine was issued for the woman when she arrived at Newark Airport, The Record reported. Christie said that the woman, a U.S. citizen, was not a resident of New Jersey and was intending to go on to New York, Christie said.

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.