WASHINGTON >> Justice Department prosecutors are preparing to fight in court to force former White House officials to testify about then-President Donald Trump’s conversations and actions around Jan. 6, according to people briefed on the matter.

At issue are claims of executive privilege that prosecutors expect the former president to make in order to shield some information from the federal grand jury as the criminal investigation moves deeper into the ranks of White House officials who directly interacted with Trump.

DOJ’s preemptive move is the clearest sign yet that federal investigators are homing in on Trump’s conduct as he tried to prevent the transfer of power to Joe Biden.

An executive privilege court fight would immediately put the Justice Department’s investigation into a more aggressive stance than even the Mueller investigation — a major years-long criminal probe into Trump while he was president. He was not ultimately charged.

Attorney General Merrick Garland has made clear in public remarks that Trump is not beyond the reach of the investigation because of his status as a former president.

Confronting the privilege issue reflects the care with which the Justice Department is taking as it faces the unusual situation of investigating of a former president for actions taken while in office. And it could bring about one of the first major court fights over the separation of powers in the Jan. 6 criminal investigation.

Ex-Pence aides

Trump’s attempt to maintain secrecy came up most recently in the federal grand jury testimony of Marc Short and Greg Jacob, close aides to former Vice President Mike Pence.

Before their recent grand jury testimony, prosecutors, along with lawyers for Short and Jacob, outlined some questions they would avoid in order to steer clear of potential privilege issues, with the expectation that they could return to those questions at a later date, the people briefed on the matter said.

Neither would answer questions about their direct interactions with Trump when they testified in the criminal investigation in recent weeks, according to two people familiar with the matter.

Short, Pence’s former chief of staff, and Jacob, his former chief counsel, both were present in an Oval Office meeting on Jan. 4, 2021, where Trump pressured Pence to go along with a plan presented by attorney John Eastman to block certification of the election results.

Despite the privilege issues, the witnesses spent hours answering questions to the grand jury about the pressure campaign on Pence, which Trump was part of, while avoiding direct questions about the former president, according to people briefed on the matter.

The questions prosecutors asked indicated that investigators are zeroing in on the role of Trump and others such as Eastman, Trump lawyer Rudy Giuliani and others in the broader scheme to block the certification of election results and to organize a set of fake electors who would keep Trump in office, according to the people briefed.

Mnuchin interviewed

The House Jan. 6 committee has interviewed former Treasury Secretary Steven Mnuchin and is in negotiations to talk to several other former members of Donald Trump’s Cabinet as it scrutinizes the days after the Capitol insurrection and discussions about whether to try and remove the then-president from office.

The negotiations come as the committee was interviewing Trump’s onetime chief of staff, Mick Mulvaney, on Thursday.

The Associated Press contributed to this report.