The travel advisory applies to non-essential travel to Guinea, Liberia and Sierra Leone. The outbreak in those countries has killed more than 700 people this year.
The Centers for Disease Control and Prevention (CDC) say the risk of the deadly disease coming to the United States remains small. The last time the federal agency issued such a travel warning was in 2003 because of a Severe acute respiratory syndrome (SARS) outbreak in Asia.
At the White House, press secretary Josh Earnest said the US is looking into medical evacuation options to bring two American aid workers diagnosed with Ebola back to the US. While the US government would facilitate the response, private companies would be used.
Although the CDC has concluded it is unlikely Ebola would spread if detected in the US, Earnest said the CDC is alerting health care workers in the US and reminding them how to isolate and deal with cases of Ebola.
The CDC has about two dozen staffers in West Africa to help try to control the outbreak. Officials announced today they will send 50 more in the next month.