CBS News reported Wednesday two volunteers with the Peace Corps have been isolated in Liberia for exposure to the Ebola virus.

Liberia has recorded 129 of the 672 deaths blamed on the virus that's spread across much of West Africa.

The Peace Corps in a statement said it was pulling its volunteers from Liberia, Sierra Leone and Guinea because of the spread of Ebola.

"The Peace Corps has enjoyed long partnerships with the government and people of Liberia, Sierra Leone and Guinea and is committed to continuing volunteers' work there," it said. "A determination on when volunteers can return will be made at a later date."

CBS said the two volunteers are in isolation and show no signs of sickness. Incubation, the report says, can last up to 21 days. Names have not been released.

At least two U.S. citizens -- Drs. Kent Brantly and Nancy Writebol -- have contracted the disease so far.

Another American, Liberian Finance Ministry consultant Patrick Sawyer, died from the virus.