BANGKOK — At a time when the administration of U.S. President Donald Trump is urging governments globally to take a hard line against refugees, asylum seekers and migrants without legal status, it is rare to hear a top American official speak out against deportation.

But last month, Marco Rubio, while fielding questions from fellow U.S. senators considering his nomination to be secretary of state, vowed to lobby Thailand not to send back a group of 48 Uyghur men from China’s predominantly Muslim Xinjiang region detained since slipping across borders in 2014 to escape persecution.