The prepared testimony of former U.S. envoy to Ukraine Kurt Volker, published Friday, provides new details about the involvement of Rudy Giuliani, President Donald Trump's lawyer, in pressuring Ukrainian officials to commit to an investigation into former Vice President Joe Biden.

According to Volker's testimony, Giuliani rejected a draft statement put forward by the Ukrainian government saying it would fight corruption in the country generally. President Donald Trump has claimed combating corruption in Ukraine was the focus of his phone call with President Volodymyr Zelensky in July, and as Common Dreams reported Friday, U.S. Ambassador to the European Union Gordon Sondland insisted in a text message provided to House Democrats that Trump was "only trying to evaluate whether Ukraine is truly going to adopt the transparency and reforms" it had promised.

But according to Volker, Giuliani "said that in his view, the statement should include specific reference to 'Burisma' and '2016,'" referring to the Ukrainian gas company where Biden's son Hunter was a board member and the 2016 election.

In his prepared remarks to the House Oversight, Intelligence, and Foreign Affairs Committees—which were made behind closed doors Thursday and released Friday—Volker said "Vice President [Biden] was never a topic of discussion" in text messages between State Department officials, in an apparent attempt to distance himself from Trump's efforts to gain information from Ukraine about Burisma and Hunter Biden.

Volker also testified that he attempted to steer Giuliani away from the notion that Biden was influenced by his son's position at Burisma while serving as vice president.

"It is not credible to me that former Vice President Biden would have been influenced in any way by financial or personal motives in carrying out his duties as vice president," Volker said. "The accusation that Vice President Biden acted inappropriately did not seem at all credible to me."

Political observers on social media noted that based on his testimony in the closed-door session with the committees, Volker appeared intent on convincing lawmakers that he had attempted to stop Giuliani and Trump from moving forward with their efforts to pressure Ukrainian officials.

Read Volker's opening testimony below: