SANTO DOMINGO, Dominican Republic (AP) — Dominican authorities on Friday resumed patrols to detain and deport migrants, the majority of them Haitians, who lack documents after a more than yearlong hiatus.

The move came weeks after the government ended a one-year period for migrants to apply for legal residency under a program that has drawn international criticism.

Bernardo Jimenez, director of the government’s immigrant detention center, said only six Haitians had been detained as of Friday. Four of them were released after proving they had enrolled in the immigration program, he said.

Officials stressed that foreigners must carry documents at all times to prove they are living legally in the Dominican Republic.

Authorities have said nearly 289,000 people enrolled in the program out of an estimated 524,000 migrants living in the Caribbean country that shares the island of Hispaniola with Haiti. Migration officials say more than 66,000 people have moved to neighboring Haiti.

Haiti’s government has warned that the actions by Dominican officials are creating a humanitarian crisis.

Relations between the two countries have grown increasingly strained since a Dominican court ruled in September 2013 that children born in the country to non-citizens did not qualify for automatic citizenship because their migrant parents were “in transit.” Most of those affected have been Haitians.