The chairmen of three House committees on Friday subpoenaed Secretary of State Mike Pompeo for documents related to President Trump’s dealings with Ukrainian President Volodymyr Zelensky.

The documents were requested as part of Democrats’ impeachment inquiry into Mr. Trump. As part of the probe, the committees are investigating whether the president sought help from his Ukrainian counterpart to dig up dirt on 2020 Democratic presidential front-runner Joseph R. Biden.

Mr. Pompeo has until Oct. 4 to turn over the documents, according to a letter signed by the chairmen of the Foreign Affairs, Intelligence and Oversight committees.

The lawmakers said they demanded the documents on Sept. 9 and again on Sept. 16. State Department officials say they are still reviewing the request, but the chairmen say Mr. Pompeo is stonewalling them.

“Your failure or refusal to comply with the subpoena shall constitute evidence of obstruction of the House’s impeachment inquiry,” Foreign Affairs Committee Chairman Eliot L. Engel, Intelligence Committee Chairman Adam B. Schiff and Oversight and Reform Committee Chairman Elijah E. Cummings wrote in a joint letter to Mr. Pompeo.

The committee heads said they have also scheduled depositions with five State Department officials over the next two weeks. Those officials include U.S. Special Envoy for Ukraine Kurt Volker, Deputy Assistant Secretary George Kent, former Ambassador Marie Yovanovitch, Counsel of the State Department T. Ulrich Brechbuhl and U.S. Ambassador to the EU Gordon Sondland.

The subpoena comes as Democrats ramp up impeachment efforts after a whistleblower said Mr. Trump pressured the Ukrainian government to investigate Mr. Biden’s son Hunter

House Speaker Nancy Pelosi initiated an impeachment inquiry this week.