(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.
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.
When I began this journey, Commissioner McAleenan charged me with aligning the mission support organizations and accelerating his priorities.
My hope is you build upon your accomplishments and embrace new opportunities, remain flexible, and continue to make CBP extraordinary.