On Aug. 28, Andrey Yermak, an aide to Ukrainian President Vlodomyr Zelensky, sent a four-word text message to Kurt Volker, a former U.S. State Department special envoy to Kiev.

"We need to talk."

Yermak followed the tweet with a link to a Politico story titled, "Trump Holds Up Military Aid Meant to Confront Russia."

"Hi Andrey — absolutely. When is good for you?" Volker responded.

Democrats late Thursday released texted messages between top diplomats that they say bolster their claim that President Trump leveraged the prospect of military aid and American influence in an attempt to force Ukraine into investigating former Vice President Joe Biden and his son Hunter Biden regarding their business dealings in the country.

Top U.S. diplomats encouraged Zelensky to conduct an investigation linked to the Bidens in return for a potentially high-profile visit to Washington with Trump, according to emails released late Thursday by House investigators following a 10-hour interview with Volker. Republicans present at the marathon-interview before three House committees appeared confident there was no “quid pro quo” during the Trump-Ukraine call.

Trump has insisted he never pressured Kiev to investigate the Bidens and any request was based on making sure the country made good on its promise to weed out corruption.

Zelensky has said he never felt pressured by Trump.

After the Volker interview, House Democrats released text messages between the top diplomats.

Volker, in a text message on the morning of a planned July 25 phone call between Trump and Zelenskiy, wrote: "Heard from White House -- Assuming President Z convinces trump he will investigate / "get to the bottom of what happened" in 2016, we will nail down date for visit to Washington."

But all that planning started to unravel when Zelensky's aide tried to lock in a date for the Trump meeting before putting out the statement on the investigations. Trump put a hold on military assistance to the country, which was depending on the funds as part of its defense of Russian separatists.

Just over a week after Yermak's message to Volker about funding, Gordon Sondland, the U.S. ambassador to the European Union, and Bill Taylor, the top U.S. diplomat to Ukraine, texted each other. They were discussing the White House's decision to cancel Trump's meeting with Zelensky in Poland.

"As I said over the phone, I think it's crazy to withhold security assistance for help with a political campaign," Taylor wrote.

"Bill, I believe you are incorrect about President Trump's intentions," Sondland wrote back. "The President has been crystal clear: no quid pro quo’s of any kind. The President is trying to evaluate whether Ukraine is truly going to adopt the transparency and reforms that President Zelenskiy promised during his campaign.”

"Bill, I believe you are incorrect about President Trump's intentions. The President has been crystal clear: no quid pro quo’s of any kind.” — Gordon Sondland, U.S. ambassador to the European Union, writing to the top U.S. diplomat in Ukraine

Sondland then recommended stopping the text exchange.

Reps. Jim Jordan, R-Ohio, and Devin Nunes, R-Calif., said Thursday’s interview with Volker “undercut” the Democratic narrative that Trump tried to interfere with an election.

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“The facts we learned today undercut the salacious narrative that Adam Schiff is using to sell his impeachment ambitions,” Jordan and Nunes said in a joint statement, referring to the chairman of the House Intelligence Committee. “We hope the American people get to read the transcript of today's testimony and see the truth."

Fox News' Morgan Phillips and the Associated Press contributed to this report.