House Democrats on Monday launched an investigation into whether President Trump and his attorney Rudolph W. Giuliani sought to manipulate the Ukrainian government into helping Trump’s reelection campaign.

In letters to the White House and State Department, top Democrats demanded records related to what they say are Trump and Giuliani’s efforts “to coerce the Ukrainian government into pursuing two politically-motivated investigations under the guise of anti-corruption activity” — one to help Trump’s former campaign manager Paul Manafort, who is in prison for illegal lobbying and financial fraud, and a second to target former vice president Joe Biden, who is seeking to unseat Trump.

“As the 2020 election draws closer, President Trump and his personal attorney appear to have increased pressure on the Ukrainian government and its justice system in service of President Trump’s reelection campaign, and the White House and the State Department may be abetting this scheme,” the chairmen of the House Intelligence, Foreign Affairs and Oversight committees wrote, citing media reports that Trump had threatened to withhold $250 million in aid to help Ukraine in its ongoing struggle against Russian-backed separatists.

Neither the White House, State Department nor Giuliani immediately responded to messages seeking comment.

“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,” House Intelligence Committee Chairman Adam B. Schiff (D-Calif.), Foreign Affairs Committee Chairman Eliot L. Engel (D-N.Y.) and Oversight Committee Chairman Elijah E. Cummings (D-Md.) said in their letter.

The committee chairmen demanded that the White House and State Department turn over by next Monday all documents and correspondence related to Manafort and Biden’s son Hunter Biden, whose past involvement with the Ukrainian energy company Burisma spurred Giuliani’s scrutiny of the former vice president.

Democrats also want any correspondence related to multiple Ukrainian officials, including Serhiy Leshchenko, a journalist turned politician who exposed how secret payments were made to Manafort by a pro-Russian political party in Ukraine; Prosecutor General Yuriy Lutsenko; and Andriy Yermak, an aide to President Volodymyr Zelensky with whom Giuliani has spoken.

They also want the full transcript and a list of participants on a July 25 call between Trump and Zelensky.