A report by The New York Times says Central American migrant children seeking asylum in the United States are being sent to Mexico, where some have been located in shelters in cities where they have no familial or other connections.

The U.S. newspaper reported Oct. 30 that expulsions have taken place under a Trump administration policy that says the actions have to be carried out to prevent the spread of COVID-19 in the U.S.

It comes days after reports that over 500 migrant children who were separated from their parents at the border, also under a 2018 Trump administration policy, still have not been reunited with family.

On Nov. 3, the newspaper reported the case of a Salvadoran migrant child whose whereabouts were reported to her sister, a legal U.S. resident, by authorities in a shelter in Mexico, where the child was allegedly taken by U.S. Border Patrol authorities even though she had no family there. The older sister had expected U.S. authorities to contact the child's family in the U.S.

The Times said it had obtained an email from U.S. Border Patrol's assistant chief, Eduardo Sanchez, saying the expulsions from the U.S. -- mostly of children from the Central American countries of El Salvador, Guatemala and Honduras -- had taken place.

According to the newspaper, this is in violation of U.S. policy, even as Mexican authorities deny they have happened. The children are supposed to be sent back to their home countries to be reunited with family.

With authorities on both sides of the border denying or not admitting publicly the transfers have happened, migrant advocates said it's hard to know how many times the practice has been applied and how many migrant children are currently separated from family in a country they have no connection to.