CNN  — 

The White House has instructed a former official who was in charge of the security clearance process to not comply with a House subpoena demanding his appearance for an interview, the latest move by the Trump administration to thwart Democratic-led investigations into all aspects of the presidency.

After a day of tense negotiations, the White House late Monday told the former official, Carl Kline, who now works at the Defense Department, to not appear at Tuesday’s deposition, contending that Democrats were seeking access to confidential information that should be off limits.

The move raises the prospect that the House Oversight Committee could seek to hold Kline in contempt, a step that Chairman Elijah Cummings warned he would take. And it’s the latest White House effort to stonewall Democratic investigations, coming the same day the Trump Organization filed a lawsuit to prevent an accounting firm from complying with Cummings’ subpoena for President Donald Trump’s past financial records.

Michael Purpura, deputy counsel to Trump, argued that Cummings’ subpoena of Kline “unconstitutionally encroaches on fundamental executive branch interests,” according to a letter obtained by CNN.

Kline’s attorney, Robert Driscoll, said his client would listen to his employer.

“With two masters from two equal branches of government, we will follow the instructions of the one that employs him,” Driscoll said in a separate letter obtained by CNN.

In a statement Tuesday, Cummings said the White House and Kline “now stand in open defiance of a duly authorized congressional subpoena with no assertion of any privilege of any kind by President Trump.”

“The White House claims that ‘under no circumstance’ will it provide to Congress any information about any specific White House employee — regardless of whether that employee lied to federal investigators about communicating with the Russians or continued working in the White House after the FBI reported derogatory information involving domestic violence.”

Cummings said he will consult with lawyers and committee members about “about scheduling a vote on contempt.”

Following Cummings’ statement Tuesday, Driscoll issued a response saying that the Maryland Democrat is “zealously playing the role he should in our constitutional system and we bear no ill will towards him.”

“We will continue to review the proceedings and make the best judgments we can,” Driscoll said.

The flurry of letters capped a day of tense talks ahead of Tuesday’s anticipated deposition with Kline, a key witness as part of Democrats’ probe into whether the White House mishandled the security clearance process for top officials, including for Jared Kushner and Ivanka Trump.

Kline, who was subpoenaed to appear before the committee Tuesday, served as the White House personnel security director for the first two years of the Trump administration. A White House official, Tricia Newbold, told the committee that at least 25 individuals had been greenlighted for security clearances despite serious concerns raised during the vetting process – and alleged that Kline retaliated against her for speaking out.

The White House had contended that Kline would not answer questions about individuals’ security clearances but would talk more generally about the process – and pushed for an official from the White House counsel’s office to attend Tuesday’s interview, something rejected by Cummings, a Maryland Democrat.

In another letter obtained by CNN, Cummings said White House counsel Pat Cipollone previously informed the committee that Kline would not appear on Tuesday unless the committee allowed someone from the White House counsel’s office “to appear with Mr. Kline in order to preserve and protect Executive Branch confidentiality interests.”

Cummings responded Monday: “The Committee will not permit a representative from your office to attend the deposition,” adding that Kline would be held in contempt if he didn’t comply with the subpoena.

This story has been updated with additional developments Tuesday.

CNN’s Lauren Fox contributed to this report.