Memo also shows Donald Trump asking Volodymyr Zelensky for a "favor"

Facing an impeachment probe in Congress, President Donald Trump was forced Wednesday to release a call transcript showing he had urged his Ukrainian counterpart to investigate rival Joe Biden -- in what Democrats slammed as a "mafia-style shakedown."

A defiant Trump insisted he had exerted "no pressure" on Kiev -- a claim echoed by Ukrainian leader Volodymyr Zelensky, who appeared side-by-side with the US president at a long-planned meeting on the sidelines of the UN General Assembly.

But the publication of the transcript -- a day after Democrats launched an official impeachment inquiry -- sent a new shockwave through Washington, including within the ranks of Trump's Republican Party, with Senator Mitt Romney calling it "deeply troubling."

Two competing narratives immediately took hold.

Trump and his allies claimed the call contained no evidence of a quid pro quo pressuring Zelensky to probe the president's top Democratic rival for the White House.

Democrats meanwhile held it up as a smoking gun, with senior lawmaker Adam Schiff describing "a classic mafia-type shakedown of a foreign leader."

"This is how a mafia boss talks: 'What have you done for us? We've done so much for you but there's not much reciprocity. I have a favor to ask you,'" Schiff charged.

"And what is that favor? Of course, the favor is to investigate his political rival, to investigate the Bidens."

The July 25 call summary -- which is not a verbatim transcript -- shows Trump saying US Attorney General Bill Barr and the president's personal lawyer Rudy Giuliani would be in touch about probing the Ukraine-related activities of Biden and his son.

'Nobody pushed me'

As Barack Obama's vice president, Biden and other Western leaders pressured Ukraine to get rid of the country's top prosecutor, Viktor Shokin, because he was seen as not tough enough on corruption.

"There's a lot of talk about Biden's son, that Biden stopped the prosecution and a lot of people want to find out about that so whatever you can do with the attorney general would be great," Trump told Zelensky in the call.

"Biden went around bragging that he stopped the prosecution so if you can look into it... It sounds horrible to me."

The transcript did not show Trump explicitly tying aid to Ukraine to Zelensky probing Biden, which has fed the calls to impeach him.

But the two did discuss a major aid package, which had been frozen by Trump at the time and was only released in recent weeks.

The memo also shows Trump asking Zelensky for a "favor" on an issue unconnected to Biden -- just after noting that the US had been "very, very good to Ukraine."

"There was no pressure whatsoever," Trump told reporters, saying Democrats had built up the exchange as the "call from hell" but that "it turned out to be a nothing call."

Speaking later at Trump's side, Zelensky insisted he had not been "pushed" by Trump during the controversial call.

"We had -- I think (a) good phone call. It was normal. We spoke about many things, and... so I think and you read it that nobody pushed me," the Ukrainian leader told reporters.

'A disgraceful thing'

In announcing the launch of impeachment proceedings on Tuesday, House Speaker Nancy Pelosi said Trump had betrayed his oath of office in seeking Ukraine's help to find dirt on Biden.

Faced with the possibility of becoming the third US president in history to be impeached, Trump has pushed back hard -- branding the probe the "single greatest witch hunt in American history... a disgraceful thing."

Pelosi had long resisted pressure from the party rank-and-file for impeachment, preferring to focus on next year's election fight.

A Quinnipiac poll released Wednesday said that only 37 percent of voters support impeaching Trump while 57 percent oppose, even if more than half disapprove of the US leader's performance.

But on Tuesday, Pelosi abandoned months of resistance, 11 days after news that an anonymous US intelligence official had filed a whistleblower complaint on Trump's alleged double-dealing with Ukraine.

Democrats made clear the White House's release of the call record would not satisfy their investigation into whether the US leader broke the law.

They are demanding the full release of the whistleblower complaint, even as the Justice Department declared that it showed no wrongdoing and said "no further action was warranted."

The next explosive episode in the rapidly unfolding impeachment drama is set for Thursday when acting director of national intelligence Joseph McGuire, who has refused to release the complaint, testifies on Capitol Hill.