President Trump's attorney Rudy Giuliani on Tuesday said he was "disappointed" in former National Security Adviser John Bolton, after reports emerged that he had called Giuliani a "hand grenade" over his Ukraine investigations - and told a top aide to alert a lawyer in the National Security Council.
Hill said Sondland appeared to be coordinating with Mick Mulvaney, the acting White House chief of staff, the person said.
On Monday, Schiff kicked out Rep. Matt Gaetz (R-FL), a member of the Judiciary Committee, from attending a closed-door impeachment inquiry hearing with former senior National Security Council official Fiona Hill. Her attorney said she would have received a congressional subpoena and would "comply and answer questions" from lawmakers.
Trump repeatedly characterises his Zelensky call as "perfect", but the whistleblower's complaint noted how some White House officials were so concerned about Trump's actions on the call that they sought to severely restrict access to its record.
Laura Cooper, the Deputy Assistant Secretary of Defence overseeing Ukraine, will testify on Friday.
Though Yovanovitch's term as ambassador was curtailed earlier than planned in May, she remains an employee of the State Department, and her testimony has been held up as a model of how Congress can use subpoenas to help officials circumvent the administration's refusal to cooperate in the impeachment probe.
In a phone call on July 25, Trump is alleged to have threatened to withhold aid to Ukraine unless a Ukrainian prosecutor looks into the Bidens.
"John Bolton knew it was wrong for the @realDonaldTrump Administration to pressure Ukraine to get dirt on an American political opponent".
Testifying on Thursday will be US Ambassador to the European Union Gordon Sondland, who shortly before Mr Trump's Ukraine call participated in several text messages with other US diplomats who expressed concern that Trump was seeking a quid pro quo for the military aid. He's expected to tell Congress that his text message reassuring another envoy that there was no quid pro quo in their interactions with Ukraine was based exclusively on what Trump told him, according to a person familiar with his coming testimony.
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No new formal offers are expected to be presented by UAW officials, according to one source familiar with the talks. Meanwhile, direct wage losses for all employees have already surpassed $ 400 million and continues to climb.
The Democrats' inquiry could prompt the House to approve articles of impeachment - formal charges - leading to a trial in the Senate on whether to remove Trump from office.
Lawmakers this week are returning from a two-week recess, with testimony from current and former administration officials on the schedule.
The committees are also scheduled to talk to Ulrich Brechbuhl, a State Department counselor, on Thursday.
"Given that we already have the call record, we don't need the whistleblower who wasn't on the call to tell us what took place during the call", Schiff said.
According to the Daily Caller News Foundation, Schiff has pulled back his preference for the whistleblower to testify after it was revealed on October 2 that the whistleblower had contact with a Schiff aide prior to filing the complaint on august 12.
Top Democrats say testimony and evidence coming in from other witnesses, and even the Republican president himself, are backing up the whistleblower's account of what transpired during Trump's July 25 phone call with Zelenskiy.
Whistleblowers are protected by USA law, and revealing their identity is a crime.
On 24 September, House Speaker Nancy Pelosi launched a formal inquiry into President Trump, following allegations from an alleged Central Intelligence Agency whistleblower that POTUS had asked Ukrainian President Volodymyr Zelensky to investigate the former vice-president and Democratic presidential candidate Joe Biden and his son Hunter, during a phone conversation that took place in July.
As talks continue over whether the whistleblower from within the U.S. intelligence community who prompted the inquiry will testify, Mr Trump weighed in on Twitter, demanding that the person testify and that the individual's identity be revealed.