The US has blocked the Mexican border at an isolated Texas town where thousands of Haitian refugees have crossed and set up camp.
Authorities are trying to stop the flow of migrants as they began flying some of them back to their homeland.
About a dozen Texas Department of Public Safety vehicles lined up near the bridge and river where Haitians have been crossing from Ciudad Acuna, Mexico, into Del Rio, Texas, for almost three weeks.
Yellow police tape is being used to block the migrants from using a small dam to walk into the US.
A Mexican police officer said migrants would not be allowed to cross any more.
Many of the migrants have lived in Latin America for years, but they are now are seeking asylum in the US as economic opportunities in Brazil and elsewhere dry up.
Thousands are living under and near a bridge in Del Rio.
Earlier on Sunday, the US sent three flights of Haitians back to their homeland. The planes are expected to arrive that afternoon in Port-au-Prince, Haiti’s capital.