Customs and Border Protection chief resigns in midst of controversy over detention facilities

The acting head of U.S. Customs and Border Protection has submitted his resignation to acting Department of Homeland Security Secretary Kevin McAleenan, as controversy swirls over conditions for illegal immigrants at the agency's detention centers.

What are the details?

John Sanders announced via email to CBP employees Tuesday that he would be stepping down effective July 5. He has been in the position since April.

According to ABC News, Sanders told the employees that in his letter to McAleenan, "I quoted a wise man who said to me, 'each man will judge their success by their own metrics.' Although I will leave it to you to determined whether I was successful, I can unequivocally say that helping support the amazing men and women of CBP has been the most fulfilling and satisfying opportunity of my career."

He added, "Don't underestimate the power of momentum as you continue to tackle some of this country's most difficult challenges." Sanders reportedly did not give an explanation for why he was leaving.

Fox News reported that Sanders' departure announcement came amid House lawmakers' continued struggle to agree on a $4.5 billion funding bill aimed at addressing the escalation humanitarian crisis at the U.S.-Mexico border. The move by Sanders also comes as tension builds over the conditions at detention centers run by CBP.

Last week, attorneys visited a remote Border Patrol station in Clint, Texas, and reported that more than 300 children were being held there without adequate food, water, or supervision, according to the Los Angeles Times. Amid outcry, the kids were transferred elsewhere, but then 127 were subsequently returned to the Clint station within days.

On Friday, Rep. Veronica Escobar (D-Texas) wrote Sanders and U.S. Border Patrol Chief Carla Provost, asking, "How is it possible that you both were unaware of the inhumane conditions for children, especially tender-age children at the Clint Station?

Anything else?

The CBP has faced increasing scrutiny as facilities are overburdened by a growing influx of migrants, and six children have died since late last year after being detained by the agency. In an interview with The Associated Press last week, Sanders told the outlet the deaths "impacted him profoundly."