House Minority Leader Kevin McCarthy, R-Calif., who is poised to become speaker in January, on Tuesday threatened to impeach Homeland Security Secretary Alejandro Mayorkas over record-high U.S.-Mexico border migrant crossings.

At a news conference near the border in El Paso, Texas, McCarthy called on Mayorkas to resign — then warned that if he does not resign, House Republicans will “investigate” whether to begin impeachment proceedings.

“He cannot and must not remain in that position,” McCarthy said. “House Republicans will investigate. Every order, every action and every failure will determine whether we can begin impeachment inquiry.”

The announcement comes as Republicans prepare to conduct broad oversight of the Biden administration during the 118th Congress. Border security and immigration will be a focus of that oversight, with Republicans eager to highlight how crossings have strained border communities since President Joe Biden took office.

Border agents recorded nearly 2.4 million encounters with migrants during fiscal 2022, the highest number on record, though some of the recorded encounters involve the same migrants making repeated attempts at crossing.

Republicans staunchly oppose the Biden administration’s decision to end pandemic-era border expulsions under Title 42 for certain migrant groups, rescind the Trump-era “Remain in Mexico” policy, and halt border wall construction.

“For the last two years, President Joe Biden and the Democrats running Congress have pushed open border policies and waged baseless attacks on our border agents,” McCarthy said.

McCarthy also promised to hold committee hearings at the border “so the Democrats can no longer hide from the crisis they have created.”

McCarthy added that he had spoken with Rep. Jim Jordan, R-Ohio, the expected chairman of the House Judiciary Committee, and Rep. James Comer, R-Ky., the expected chairman of the House Oversight Committee. Both those panels are poised to play a major role in oversight of the government’s border policies and an impeachment inquiry against Mayorkas.

“Leader McCarthy is right,” Jordan said in a news release after the conference. “Americans deserve accountability for the unprecedented crisis on the southwest border. Republicans will hold Secretary Mayorkas accountable for his failure to enforce immigration law and secure the border through all means necessary.”

White House Press Secretary Karine Jean-Pierre on Tuesday called the trip a “political stunt” and said Biden secured record funding for the Department of Homeland Security, put forward a comprehensive immigration bill and has taken other steps to address criminal smuggling networks and fentanyl trafficking.

“So, we have a plan. We’ve been putting that forward. McCarthy has no plan. The Republican Party has no plan,” Jean-Pierre said.