Part of a fast-rising influx of Cubans, they walk out to a Laredo street and are greeted by volunteers from Cubanos en Libertad, or Cubans in Freedom, who help them arrange travel to their American destination — often Miami — and start applying for work permits and federal benefits like food stamps and Medicaid, available by law to Cubans immediately after their arrival.

The friendly reception given the Cubans, an artifact of hostile relations with the Castro government, is a stark contrast with the treatment of Central American families fleeing violence in their countries. And it is creating tensions in this predominantly Mexican-American city, where residents saw how Central American migrants, who came in an influx in 2014, were detained by the Border Patrol and ordered to appear in immigration courts.

“The people here are starting to feel resentment,” said Representative Henry Cuellar, Democrat of Texas, whose congressional district includes the city. “They are asking, is it fair that the Cubans get to stay and the Central Americans are being deported?”