US warns its ‘darker-skinned’ citizens of Dominican Republic’s migrant crackdown

US officials in the Dominican Republic are warning "darker-skinned" Americans they are at risk of being swept up in the country's crackdown on Haitian migrants.

The advice from the US embassy in Santo Domingo suggests that authorities there are using a person's appearance as a criteria for detention of those suspected of being in the country illegally.

The Dominican Republic says it has deported 43,900 migrants, mostly Haitians, between July and October in an operation it insists is necessary for national security amid growing unrest, gang crime and a fuel blockade inside its only neighbour on the island of Hispaniola.

The expulsions include hundreds of children sent to Haiti without their parents, according to Unicef, reported by CNN.

Several countries and human rights agencies have condemned the program of mass arrests and deportations, criticism the Dominican Republic government says it "profusely rejects".

The US embassy's warning came in a bulletin about "ongoing Dominican migration enforcement" issued at the weekend.

"Dominican migration agents have conducted widespread operations aimed at detaining those they believe to be undocumented migrants, especially persons of Haitian descent," it says.

"In some cases, authorities have not respected these individuals' legal status in the Dominican Republic or nationality. These actions may lead to increased interaction with Dominican authorities, especially for darker-skinned US citizens and US citizens of African descent."

It goes on to warn of reports of detainees being held "without the ability to challenge their detention, and without access to food or restroom facilities, sometimes for days at a time".

The US maintains its own program for the expulsion of Haitian migrants, for which it has also been heavily criticized.

In defending its position on the deportations, the Dominican Republic says there is "no evidence" of any systemic human rights violations, as suggested in the US embassy's bulletin.

Its ministry of foreign relations said in a statement: "The Dominican government never could have imagined there would be such a harsh insinuation made about our country, much less from an ally that has been subject to accusations of xenophobic and racist treatment of migrants, including in parts of its own population."

Deportations from the Dominican Republic since have escalated, and the country's government has increasingly militarized its border, even beginning construction of a border wall.

He said his country "has been more affected" by Haiti's problems and steady migration and "more supportive than any other country in the world".

"You can't ask anything more from the Dominican Republic. We're going to continue the deportations and next week we're going to increase them," he said.

Additional reporting by the Associated Press