The Biden administration's special envoy to Haiti has resigned, protesting "inhumane" large-scale expulsions of Haitian migrants to their homeland wracked by civil strife and natural disaster, U.S. officials said Thursday.

Daniel Foote was appointed to the position only in July, following the assassination of Haiti's president. Even before the migrant expulsions from the small Texas border town of Del Rio, the career diplomat was known to be deeply frustrated with what he considered a lack of urgency in Washington and a glacial pace on efforts to improve conditions in Haiti.

Foote wrote Secretary of State Antony Blinken that he was stepping down immediately "with deep disappointment and apologies to those seeking crucial changes."

"I will not be associated with the United States inhumane, counterproductive decision to deport thousands of Haitian refugees and illegal immigrants to Haiti, a country where American officials are confined to secure compounds because of the danger posed by armed gangs to daily life," he wrote. "Our policy approach to Haiti remains deeply flawed, and my policy recommendations have been ignored and dismissed, when not edited to project a narrative different from my own." 

Two U.S. officials with direct knowledge of the matter confirmed the resignation on condition of anonymity because they were not authorized to discuss it publicly. 

One official, who was not authorized to publicly discuss personnel matters and spoke on condition of anonymity, said that Foote had consistently sought greater oversight of Haiti policy and that the administration did not believe his requests were appropriate.

Foote's sudden departure leaves a void in U.S. policy toward Haiti and adds another prominent, critical voice to the administration's response to Haitians camped on the Texas border. The camp has shrunk considerably since surpassing more than 14,000 people on Saturday – many of them expelled and many released in the U.S. with notices to report to immigration authorities. 

The White House is facing sharp bipartisan condemnation. Democrats and many pro-immigration groups say efforts to expel thousands of Haitians without a chance to seek asylum violates American principles and their anger has been fueled by images that went viral this week of Border Patrol agents on horseback using aggressive tactics against the migrants.

The expulsion flights to Haiti began Sunday and there were 10 by the end of Tuesday, according to Haitian officials. U.S. officials say they are ramping up to seven flights a day, which would mark one of the swiftest, large-scale expulsions from the U.S. in decades.

Foote served previously in Haiti as deputy chief of mission and is a former ambassador to Zambia. In new role, he worked with the U.S. ambassador to support Haiti after the assassination of President Jovenel Moise.