ESTA holders who are dual citizens of Iran, Iraq, Sudan and Syria had their ESTAs revoked in January 2016, and will be required to apply for a regular tourist visa at a US foreign mission. ESTA holders who have traveled to Iran, Iraq, Libya, North Korea, Somalia, Sudan, Syria or Yemen on or after 1 March 2011 will not have their ESTAs revoked, but will be refused entry if their travel is discovered by the CBP on arrival unless they qualify for a waiver. The Secretary of Homeland Security may waive these restrictions if he determines that such a waiver is in the law enforcement or national security interests of the United States. Such waivers will be granted only on a case-by-case basis. As a general matter, categories of travelers who may be eligible for a waiver include individuals who traveled to these countries on behalf of international organizations, regional organizations, and sub-national governments on official duty; on behalf of a humanitarian NGO on official duty; or as a journalist for reporting purposes.