WASHINGTON: US Republicans announced impeachment proceedings Wednesday against Joe Biden’s homeland security chief over the worsening border crisis, as they seek to cement immigration as a major issue in November’s presidential election.

Up to 10,000 migrants have been detained daily after crossing illegally from Mexico in what Republicans describe as a humanitarian disaster, while the White House and lawmakers have failed to agree on reforms to stem the influx.

Republicans in Congress, who concluded a probe into Homeland Security Secretary Alejandro Mayorkas in December, accuse the Democrat of creating a national security emergency.

“Our investigation made clear that this crisis finds its foundation in Secretary Mayorkas’ decision-making and refusal to enforce the laws passed by Congress, and that his failure to fulfill his oath of office demands accountability,” House Homeland Security Committee chairman Mark Green said in a statement.

“The bipartisan House vote in November to refer articles of impeachment to my committee only served to highlight the importance of our taking up the impeachment process.” Mayorkas would be the first Cabinet official impeached since Secretary of War William Belknap in 1876.

A majority of the House would be required to vote that he had committed “high crimes and misdemeanors,” prompting a Senate trial that would boot him from office if two-thirds of senators voted to convict.