Rep. Adam Schiff, head of the House Intelligence Committee, on Wednesday said Democrats will consider any White House efforts to stonewall the Ukraine investigation as obstruction of justice.

“It is why I saw the White House needs to understand that any action like that forces us to litigate or have to consider litigation will be considered further evidence of obstruction of justice,” the California Democrat said, noting that obstruction was one of the articles of impeachment against President Richard Nixon in 1974.

“We are not fooling around. We do not want this to drag on for months and months, which appears to be the strategy,” said Schiff, who was speaking at House Speaker Nancy Pelosi’s weekly news briefing on Capitol Hill.

Schiff and other Democratic committee chairs are seeking information related to President Trump’s July 25 phone call with Ukraine President Volodymyr Zelensky, in which Trump requested an investigation into Democratic presidential candidate Joe Biden and his son Hunter Biden.

Secretary of State Mike Pompeo, who admitted Wednesday he was on the call that sparked the formal impeachment inquiry, is blocking five State Department officials from giving depositions.

Pompeo accused the House committees of trying to “intimidate, bully, & treat improperly” his employees.

Schiff said he’s “deeply concerned” with Pompeo’s efforts to “potentially interfere with witnesses” who could speak to the allegations in a damning whistleblower complaint that was unclassified last week.

“If they are going to prevent witnesses from coming forward to testify on the allegations in the whistleblower complaint, that will create an adverse inference that those allegations are in fact correct,” Schiff said.

The whistleblower alleges the White House tried to cover up Trump’s repeated requests that Ukrainian officials launch a probe of the Bidens.

“In the course of my official duties, I have received information from multiple US Government officials that the President of the United States is using the power of his office to solicit interference from a foreign country in the 2020 US election,” the complaint said.

Meanwhile, Trump on Wednesday continued to fight back against the impeachment probe. The president called for the resignation of “lowlife” Schiff, bashed Democrats’ investigations as “bulls–t” and referred to the whistleblower as a “spy.”