More than two dozen lawmakers want the United States government to ban travelers from the West African countries hit hardest by the Ebola virus until the outbreak is under control.

Twenty-three Republican and three Democratic members of the U.S. House of Representatives signed a letter released on Thursday to President Barack Obama asking the State Department to impose a travel ban and restrict visas issued to citizens of Guinea, Liberia and Sierra Leone.

In the letter, dated Oct. 8, they also asked U.S. health and border control officials to consider quarantine for anyone who arrives from the affected nations after being exposed to Ebola until 21 days have passed, the period in which they would show signs of the illness.