In what supporters of House Democrats' impeachment inquiry into President Donald Trump called a "bombshell," a key witness provided new written testimony to lawmakers Tuesday that confirms and details a quid pro quo which involved the Trump administration pressuring Ukraine to launch a politically advantageous corruption probe.

U.S. Ambassador to the European Union Gordon Sondland's three-page amendment to his testimony, described by some reporters and political commentators as a "reversal," serves as an update to his 10-hour appearance last month before members of the House Intelligence, Oversight and Reform, and Foreign Affairs committees.

Breaking: Gordon Sondland told Ukraine: No military aid until they PUBLICLY committed to investigating Trump's potential 2020 opponent. That is the quid pro quo. Even Sondland, a who bought his job with a $1M Trump inauguration donation, knew it. https://t.co/3eeLdJwPtl — Swing Left (@swingleft) November 5, 2019

Democratic House Speaker Nancy Pelosi announced the impeachment inquiry into Trump in late September in response to a whistleblower complaint about Trump's July 25 phone call with Ukrainian President Volodymyr Zelensky. The complaint raised concerns about Trump withholding $391 million in military aid to pressure Zelensky into publicly announcing a corruption investigation of the Ukrainian energy firm Burisma, which had employed the son of former Vice President Joe Biden, a key political rival in the 2020 presidential race.

In the weeks since Pelosi's announcement, House impeachment investigators have heard lengthy testimonies from several witnesses within the federal government. Along with Sondland's new statement Tuesday, the committees released excerpts (pdf) from Sondland's original Oct. 17 testimony as well as excerpts (pdf) from the Oct. 3 testimony of Kurt Volker, former U.S. special representative for Ukraine negotiations.

READ: Sondland submitted this amendment to his testimony, saying other witnesses refreshed his recollection tha tmilitary aid was withheld as part of Trump's push to get a Biden investigation going. pic.twitter.com/AnQsm0P2Ag — Kyle Cheney (@kyledcheney) November 5, 2019

In Sondland's newly revised testimony, the ambassador wrote that reading the opening statements of career diplomat William Taylor and Timothy Morrison, the senior director for Europe and Russia at the National Security Council, had "refreshed my recollection about conversations involving the suspension of U.S. aid."

"I always believed that suspending aid to Ukraine was ill-advised, although I did not know (and still do not know) when, why, or by whom the aid was suspended," Sondland said Tuesday. "However, by the beginning of September 2019... I presumed that the aid suspension had become linked to the proposed anti-corruption statement."

Sondland claimed Tuesday he now recalled that after a "large meeting" in Warsaw on Sep. 1, he had a one-on-one conversation with Zelensky aide Andriy Yermak "where I said that resumption of U.S. aid would likely not occur until Ukraine provided the public anti-corruption statement that we had been discussing for many weeks."

Rep. Ted Lieu (D-Calif.), a member of the House Judiciary and Foreign Affairs committees, tweeted in response to Sondland's statement Tuesday: "Quid Pro Quo. Something for Something. This is what Amb Sondland and other witnesses have established."

Quid Pro Quo. Something for Something. This is what Amb Sondland and other witnesses have established. In this case, the second something was illegal. No one, not even @POTUS, is allowed to solicit foreign interference in our elections. No one is above the law.#TruthExposed https://t.co/qV4EluWmce — Ted Lieu (@tedlieu) November 5, 2019

Impeachment HQ—a joint project of Stand Up America and Defend the Republic—noted in an email to supporters Tuesday that in addition to the military aid for corruption probe quid pro quo, "Sondland's testimony confirms another quid pro quo: that the meeting between Donald Trump and Ukrainian President Volodymyr Zelensky was conditioned on announcing investigations into the Bidens."

Meanwhile, the group added, "Kurt Volker's testimony debunks the claims that Donald Trump's demand for an investigation was focused on rooting out general corruption."

