The United States imposed new travel restrictions on citizens of Hungary on Tuesday

over concerns that the identities of nearly 1 million foreigners granted Hungarian passports

over nine years were not sufficiently verified, according to the U.S. Embassy and a government official.

The restrictions apply to the U.S. Visa Waiver Program, which allows passport holders from 40 countries

To enter the United States for business or tourism without a visa for up to 90 days.

The validity period of travel for Hungarian passport holders under the Electronic System for Travel Authorization was reduced from two years to one year,

They are the only such restrictions among the 40 participating states in the Visa Waiver Program.

A senior U.S. government official said the change followed years of failed efforts by the U.S.

The official spoke anonymously in order to candidly characterize diplomatic engagements.

The United States earlier recategorized Hungary as a provisional member of the Visa Waiver Program due to the concerns.