By Patricia Zengerle and Jonathan Landay
WASHINGTON (Reuters) - An official at the White House's national security council said he heard the U.S. ambassador to the European Union press Ukrainian officials to investigate Joe Biden and his son, according to a transcript released on Friday by Democrats leading the impeachment probe of President Donald Trump.
Alexander Vindman, a U.S. Army lieutenant colonel and Ukraine expert on Trump's NSC staff, said there was "no ambiguity" in the remarks he said were made at a meeting in the White House on July 10 by Gordon Sondland, a Trump donor-turned-diplomat now heading the U.S. delegation to the EU.
"He was calling for something, calling for an investigation that didn’t exist into the Bidens and Burisma," Vindman said. "My visceral reaction to what was being called for suggested that it was explicit. There was no ambiguity."
The transcript was one of many released this week by House committees investigating whether Trump pressured Ukraine to carry out a corruption probe into a political rival. Former Vice President Joe Biden is one of Trump's main Democratic rivals as the president runs for re-election in 2020.
Biden's son, Hunter, was on the board of directors of Burisma, a Ukrainian gas company.
Earlier on Friday, Trump said he was unconcerned about the impeachment inquiry and dismissed the release of transcripts of testimony by U.S. diplomats and others. He also criticized House Democrats for moving their inquiry into the public eye with open, televised hearings next week.
"They shouldn't be having public hearings; this is a hoax," Trump, who has denied any wrongdoing, told reporters.
Trump accused Democrats of looking for people who hated him to testify in the probe and said he was not familiar with most of the witnesses, who include a number of top U.S. State Department officials.
"I'm not concerned about anything. The testimony has all been fine. I mean, for the most part, I never even heard of these people. I have no idea who they are," he said.
House investigators are still pursuing testimony from witnesses behind closed doors, including from acting White House Chief of Staff Mick Mulvaney, who is Trump's top aide as well as director of the White House's Office of Management and Budget.
Mulvaney was subpoenaed on Thursday night to appear but did not show up on Friday. His outside legal counsel informed investigators that his client had been directed by the White House not to comply with the subpoena and asserted "absolute immunity," a congressional aide said.
Mark Sandy, associate director for national security programs at OMB, also was called to testify and did not show up.
The White House previously has said it would not cooperate with the congressional investigation, which was triggered by a whistleblower complaint about Trump's July 25 telephone call with Ukrainian President Volodymyr Zelenskiy.
Lawmakers wanted to question the two officials about their knowledge of OMB's decision last summer to block, without explanation to Congress, nearly $400 million in security aid for Ukraine that had been approved by lawmakers.
(Reporting by Patricia Zengerle, Susan Cornwell, Makini Brice, Alexandra Alper and Susan Heavey; Additional reporting by Eric Beech and Mark Hosenball; Writing by Paul Simao; Editing by Andy Sullivan and Alistair Bell)