Trump points to tweets the whistleblower's attorney Mark Zaid published 10 days after the president took office; chief White House correspondent John Roberts reports.
US House Democrats, running impeachment proceedings against US President Donald Trump, released transcripts of testimonies of two witnesses - Trump's adviser on Russia Fiona Hill, and National Security Council Director for European Affairs Alexander Vindman.
"I think there's more evidence to the effect that the president shook down Ukraine, tried to cover it up, and threatened to and then withheld security assistance to Ukraine than there is evidence that the sun will come up in the east tomorrow", Heck said.
For almost a year, Giuliani has pursued unsubstantiated allegations that Biden pushed to fire a Ukrainian prosecutor to stop him from investigating Burisma, the Ukrainian energy company on the board of which Biden's son, Hunter, served.
"He was calling for something, calling for an investigation that didn't exist into the Bidens and Burisma", Lt-Col Vindman said.
Vindman said it was the first time he'd encountered that after taking part in four or five presidential-level phone calls.
Into the Bidens? the investigators pressed. "And to the best of my knowledge, he's never suggested that he was promoting USA policy", Kent said. "There was no ambiguity".
The inquiry enters a critical phase next week when House committees hold impeachment hearings in public. The testimony has all been fine.
State Department official Catherine Croft testified last week that Mulvaney had put a hold on almost $400 million in military aid to Ukraine four months ago - before Trump's phone call with Zelensky that spawned a whistle-blower report, and the impeachment investigation.
Vindman listened in to the July 25 call where Trump personally appealed to Ukrainian President Volodymyr Zelenskiy for the investigations of political rival Joe Biden and his family and also Ukraine's role in the 2016 USA presidential election.
Trump insisted earlier Friday he has not been damaged by testimony detailing efforts by him and his administration to pressure Ukraine.
Speaking to reporters as he left on a campaign trip to Atlanta, Trump said he was "not concerned about anything" that has been disclosed so far. House impeachment investigators have conducted a series of closed-doors interviews with former and current Trump administration and released transcripts of depositions by several witnesses. "They asked for it and I gladly give it". Pence has said he and the Ukrainian president did not discuss Biden during their closed-door meeting, but they did discuss the White House's decision to halt security aid meant to counter Russian aggression. Democrats believe that Trump withheld United States aid for Ukraine to "pressure" its president, Volodymyr Zelenski, in a 25 July telephone conversation, to start a criminal probe into Joe Biden, a possible Democratic opponent in the 2020 USA presidential election.