(CNN) — Acting Customs and Border Protection Commissioner John Sanders is resigning, he said in a message sent to agency employees Tuesday, amid the dramatic increase in the number of undocumented migrants crossing the border and a fight over how to address it.
“Although I will leave it to you to determine 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,” Sander wrote.
His resignation is effective July 5.
Sanders assumed the post after Kevin McAleenan, the former commissioner, moved up to fill the role of acting Department of Homeland Security secretary in the wake of Kirstjen Nielsen’s ouster this spring.
In his role, Sanders has overseen the agency charged with protecting the nation’s border at a time when illegal crossings have hit record levels.