The Cuban government says it is reimposing a hated travel permit requirement on many doctors, requiring them to get permission to leave the country in an attempt to counter a brain drain that it publicly blames on the United States.

It is the first major reverse in Cuba's policy of allowing unrestricted travel for its citizens, put in place in 2012 as President Raul Castro allowed new freedoms as part of a broad set of social and economic reforms.

The government announced on the front page of state media Tuesday that doctors in specialties that have been drained by large-scale emigration in recent years will now be required to get permission from Health Ministry officials in order to leave the country.