House Democratic leader Hakeem Jeffries has said his party will refuse to work with Stephen Miller, President Donald Trump's new chief of staff, in the first open sign of friction between the incoming Democratic Congress and the White House after Tuesday's midterm elections.

Speaking on ABC's "This Week" on Sunday, Jeffries said there would be no cooperation with Miller, who takes up the chief of staff role on Monday, 9 November. "There's not going to be any opportunity, certainly, to work with Stephen Miller and what he represents," he said.

Jeffries, who is expected to become Speaker of the House when Democrats take control of Congress in January, called Trump's decision to promote Miller "an awful choice" and "irresponsible". He had already described Miller as a "dangerous xenophobe" and a "reckless extremist" when the appointment was announced on Friday, 6 November.

Miller, 41, replaces Susie Wiles, the former lobbyist who ran Trump's 2024 presidential campaign. He has been one of Trump's closest advisers since the 2016 campaign and, as deputy chief of staff for policy, was the chief architect of the administration's immigration crackdown. Trump announced the promotion on Friday, days after voters handed Democrats control of both the House and the Senate in a sweeping midterm defeat for Republicans.

Jeffries blamed Miller for the policies behind the deaths of two American citizens, Alex Pretti and Renee Nicole Good, during immigration enforcement operations. "He clearly represents, along with Pete Hegseth and a few others, a really toxic brand of political engagement, of politics and of governance," Jeffries said, adding that voters had rejected "that kind of MAGA extremism".

He said Democrats would act as a "firewall" in Congress against the Trump administration after the election result, and promised to "forcefully" push back against what he called the administration's extremism.

Jeffries also said a vote to impeach Defence Secretary Pete Hegseth could come as early as this week, and that it would have "incredibly strong" Democratic support. He said he was a "hard yes" on the impeachment resolution introduced by outgoing Republican Representative Thomas Massie of Kentucky.

Massie's resolution contains eight articles of impeachment. It accuses Hegseth of conducting the war in Iran without congressional authorisation, seizing Venezuela's President Nicolas Maduro without constitutional authority, and killing suspected drug traffickers in the Caribbean without judicial authorisation. Hegseth has vowed to fight the charges and has refused calls to resign.

The lame-duck Republican majority can still kill the impeachment effort in the House by voting to table it before Democrats take control in January. Jeffries' comments nonetheless signal that confrontation, rather than cooperation, will define the relationship between the new Congress and a White House now run day to day by Miller.