The Trump administration’s landing team will arrive at the Pentagon on Monday and be led by Michael Duffey, a former deputy chief of staff at the agency during the president-elect’s first term, according to four people with knowledge of the decision and internal documents obtained by POLITICO.

Duffey, who served in several roles in the first Trump administration, ensured the continuation in 2019 of Trump’s controversial hold on U.S. military aid to Ukraine after career officials raised questions about the legality of the move. That hold, which Duffey assisted with keeping in place while at the Office of Management and Budget, helped lead to Trump’s first impeachment.

POLITICO earlier reported that Robert Wilkie, a former Veteran Affairs secretary, would lead the Defense Department transition effort, but his name was missing from the list on Sunday.

He said in an interview on Sunday evening that he is still leading Trump’s policy implementation teams for the Pentagon and Veterans Affairs. Wilkie said he made recommendations on a landing team and filling positions at the Pentagon but did not handle the personnel side.

The Trump administration’s agency review team at the Pentagon contains nearly a dozen people. The list provided to POLITICO includes former Pentagon official Ralph Cacci; House Speaker Mike Johnson’s legislative director Jay Hurst; Dane Hughes, who serves as a staffer on the House Armed Services Committee; former acting Army general counsel Earl Guy Matthews; and House Judiciary Committee staffer and former White House Office of Presidential Personnel official Jimmy Sapp.

Bryn Woollacott, a national security adviser to Rep. Ken Calvert (R-Calif.) is also on the list, as is Thomas DiNanno, a former assistant secretary of state for arms control, verification and compliance during the first Trump administration.

John Troup Hemenway, a former White House personnel office staffer, Bradley Hansell, a former National Security Council director, and Gregory Halsted Pejic are also on the list of those who will arrive at the Pentagon on Monday.

The Trump transition team did not directly comment on the names. “As per the Transition MOU, the White House is receiving landing team names. Some teams have begun connecting with their counterparts at agencies,” Trump-Vance Transition spokesperson Brian Hughes said in a statement.

The arrival of the Trump administration’s landing team at the Pentagon comes amid frustration within the president-elect’s orbit over the slow pace of staffing the agency.

“They don’t like the way things are spiraling so they’re just looking for shakeups,” said a person familiar with the transition, who like others contacted for this story was granted anonymity to talk about personnel moves before they are announced.

One person who is applying for a DOD appointment said unlike some other departments staffing up, they and their friends applying to Pentagon jobs haven’t been called down to Mar-a-Lago for job interviews yet.