The US special envoy to Haiti has resigned in protest at what he described as his country's "inhumane" deportation of migrants from the Caribbean island nation.
The State Department revealed Daniel Foote's resignation on Thursday.
Migrants from Haiti and other countries have flocked to Del Rio on the US-Mexican border in the southern state of Texas, in hopes of being granted asylum in the US.
Media reported that US immigration authorities have sent more than 1,400 migrants back to Haiti since Sunday.
In a letter addressed to Secretary of State Antony Blinken, Foote wrote, "I will not be associated with the United States' inhumane, counterproductive decision to deport thousands of Haitian refugees and illegal immigrants to Haiti." He said that "the collapsed state is unable to provide security or basic services" to its people.
Haiti is among the world's poorest countries. The situation in the country has been particularly unstable of late. The nation's president was assassinated in July and more than 2,000 people were killed when a major earthquake struck in August.
Public criticism has been mounting as video images of border patrol agents on horses flinging reins and charging at migrants have spread on social media.