The 3 House committees investigating President Trump and Ukraine have sent at least 8 letters — obtained by Axios — to key Trump administration officials over the past few days to demand that they appear as part of the rapidly expanding impeachment inquiry.The state of play: If everyone complies with the requests from the Intelligence, Foreign Affairs and Oversight committees, Democrats will have interviewed 11 administration officials by the end of next week. Democratic committee sources tell Axios that the accelerated pace of their efforts is directly in line with Speaker Nancy Pelosi's plan to wrap up the impeachment inquiry by the end of 2019. If the hours-long depositions of officials who have already appeared before the committees are any indication, Democrats are being incredibly thorough in their questioning.The coming schedule, per the letters obtained by Axios:Thursday, Oct. 17, 9:30am: EU Ambassador Gordon Sondland (the request was sent on Oct. 14).Friday, Oct. 18, 8:00 am: Deputy Assistant Secretary for Russia, Ukraine and Eurasia Laura Cooper (the request was sent on Oct. 11).Tuesday, Oct. 22, 9:30am: Acting Ukraine Ambassador Bill Taylor (the request was sent on Oct. 14).Wednesday, Oct. 23, 9:30am: Associate Director for National Security Programs at the Office of Management and Budget Michael Duffey (the request was sent on Oct. 11).Thursday, Oct. 24, 9:30am: Acting Assistant Secretary for International Security Affairs Kathryn Wheelbarger (the request was sent on Oct. 11).Friday, Oct. 25, 9:30am: Acting Office of Management and Budget Director Russell Vought (the request was sent on Oct. 11). Already appeared: Kurt Volker, Trump's former special envoy to UkraineMarie Yovanovich, former Ukraine ambassadorFiona Hill, Trump's former Russia advisorDeputy Assistant Secretary of State George KentAmbassador P. Michael McKinley, the former senior adviser to Secretary of State Mike PompeoGo deeper: House Democrats tap impeachment gusherHouse Democrats' impeachment roadmapTrump-Ukraine scandal: The key players, dates and documents