A federal judge in Boston has told the Trump administration it must to maintain custody of migrants whom the US government has allegedly flown to South Sudan or other countries in recent days amid heightened concerns over the administration’s aggressive approach to deportations.

A federal district court judge in Boston ruled on Wednesday that the Trump administration’s attempt to send several immigrants from other countries to South Sudan violated a court order blocking the government from deporting people to third countries without allowing them to object to their removal.

A federal judge ruled on Wednesday that the U.S. government violated his court order by attempting to deport migrants to South Sudan, opening another front in a battle between Donald Trump and judges who have imposed checks on the Republican president's hardline immigration policies.