Homeland Security Secretary Alejandro Mayorkas will testify before lawmakers on Tuesday, three days after the country's top border official, Chris Magnus, resigned under what he said was pressure from Mayorkas.
Magnus, who held the role of U.S. Customs and Border Protection commissioner since December 2021, resigned in a letter on Saturday to President Joe Biden.
A day earlier, Magnus said he had been pressured by Mayorkas to step down or be fired.
It was the most significant staffing shakeup in Biden's Democratic administration to follow last week's U.S. midterm election vote and signals that record border crossings remain a concern under Biden, a Democrat.
FBI Director Christopher Wray and National Counterterrorism Center Director Christine Abizaid will also testify in the U.S. House Homeland Security Committee hearing, which focuses on security threats.