Three Democratic committee leaders wrote to the White House Tuesday demanding that it stop stonewalling attempts to investigate the President’s Ukraine-related actions — or else.

In a letter to White House counsel Pat Cipollone, the chairmen of the House Foreign Affairs, Intelligence and Oversight Committees said that Trump “must immediately abandon his stonewalling of Congress.”

Failure to cooperate by Thursday, they said, “will compel our Committees to resort to escalated measures.”

They were pushing for answers to a two-week-old letter that they said the White House has not acknowledged.

In it, the chairmen requested documents related to Trump and his lawyer Rudy Giuliani reportedly pressuring the Ukrainian government to investigate Joe Biden’s son. They specifically mentioned the July 25 call between Trump and Ukrainian President Volodymyr Zelensky, in which Trump reportedly pressured Zelensky on the investigation.

“If the President is trying to pressure Ukraine into choosing between defending itself from Russian aggression without U.S. assistance or leveraging its judicial system to serve the ends of the Trump campaign, this would represent a staggering abuse of power, a boon to Moscow, and a betrayal of the public trust,” Reps. Eliot Engel (D-NY), Adam Schiff (D-CA) and Elijah Cummings (D-MD) wrote in the Sept. 9 letter.