Following the Executive Order signed on Friday, January 27, 2017 titled, “Protecting the Nation from Foreign Terrorist Entry into the United States”, the United States Department of State has announced that it has provisionally revoked all valid nonimmigrant and immigrant visas of nationals of Iraq, Iran, Libya, Somalia, Sudan, Syria, and Yemen with the exception of the following nonimmigrant visa classifications: A-1, A-2, G-1, G-2, G-3, G-4, NATO, C-2, or certain diplomatic visas, or any visa exempted on the basis of a determination made by the Secretaries of State and Homeland Security pursuant to section 3(g) of the Executive order on a case-by-case basis and when in the national interest.
The full text of the revocation directive can be found at http://www.politico.com/f/?id=00000159-f6bd-d173-a959-ffff671a0001.