New York and New Jersey will automatically quarantine medical workers returning from Ebola-hit West African countries, and the U.S. government is considering the same step after a doctor who treated patients in Guinea came back infected, officials said on Friday.

The steps announced by the two states, which go beyond the current restrictions being imposed by President Barack Obama's administration on travelers from Liberia, Sierra Leone or Guinea, came as medical detectives tried to retrace the steps in New York City of Dr. Craig Spencer, who tested positive for Ebola on Thursday.

The new policy applies to medical workers returning from the region through John F. Kennedy International Airport in New York and Newark Liberty International Airport in New Jersey. In the first instance of the new move, a female health care worker who had treated patients in West Africa and arrived at Newark airport was ordered into quarantine.