Biden Accepts Top U.S. Border Official Magnus's Resignation

The White House statement comes a day after U.S. media reported that Magnus had been asked to resign or was fired in a sign of tensions within Biden's administration over a record number of migrant crossings at the U.S.-Mexico border.

"I am submitting my resignation effective immediately but wish you and your administration the very best going forward. Thank you again for this tremendous opportunity," Magnus' letter said.

Deputy Commissioner Troy Miller will serve as the Acting Commissioner beginning immediately, according to a letter signed by Secretary of Homeland Security Alejandro Mayorkas, who oversees Customs and Border Protection.

The number of migrant arrests at the U.S.-Mexico border has soared to record highs under Biden, a Democrat who took office in 2021, fueling attacks by Republicans who say his policies are too lenient. Biden officials have said they aim to create a more orderly and humane immigration system, but have struggled to handle the operational and political challenges that have accompanied the high number of crossings.

Migration experts say poverty, violence and food insecurity are factors driving migrants to leave Guatemala, Honduras and El Salvador.

Magnus, 62, was confirmed in December as commissioner of the CBP, a 60,000-strong agency that oversees border security, trade and travel. Magnus had worked for police departments in Michigan, North Dakota and California before becoming the police chief in Tucson, Arizona, in 2016.

When Biden nominated Magnus for the role in 2021, the White House touted him as a reformer focused on establishing community trust in law enforcement and holding officers accountable.