WASHINGTON • Two former officials who were engaged in the Trump administration's dealings with Ukraine will meet United States congressional committees starting this week, as the impeachment inquiry into US President Donald Trump gains steam.
Congressional staff were also due to attend a briefing at Capitol Hill yesterday by the State Department's inspector-general, Mr Steve Linick, according to two sources familiar with the situation.
Staff members from the Senate and House of Representatives Foreign Affairs and Foreign Relations, Intelligence, Oversight and Appropriations committees were invited to the briefing.
The session was expected to address Ukraine-related documents that have been subpoenaed by House committees.
Following a whistle-blower complaint last week, Democrats are looking into Mr Trump's request to Ukrainian President Volodymyr Zelensky during a July 25 phone call to investigate former vice-president Joe Biden, a leading contender in the Democratic race to run against Mr Trump, a Republican, in the 2020 election.
The unidentified whistle-blower is said to be an intelligence agent who accused Mr Trump of soliciting foreign interference for his personal political benefit.
Mr Trump has denied wrongdoing and assailed the probe.
Mr Kurt Volker, who resigned last week as Mr Trump's special representative for Ukraine, was to go to Capitol Hill to give a deposition to House staff today, the day he had been asked to appear.
Ms Marie Yovanovitch, who was the US ambassador to Ukraine until she was abruptly recalled in May, has agreed to give a deposition on Oct 11, not yesterday as originally requested.
With their deep knowledge of Ukraine, testimony by Ms Yovanovitch and Mr Volker could be especially important to the impeachment probe formally launched by House Speaker Nancy Pelosi last week.
The inquiry could lead to approval of articles of impeachment - or formal charges - against Mr Trump in the House.
That would lead to a trial in the Senate on whether to remove him from office. But the President's fellow Republicans control that Chamber and have shown little appetite for removing him.
Ms Yovanovitch was ordered back to Washington two months before the end of her three-year tour in Kiev. The career diplomat, who has served during both Republican and Democratic administrations, had been the subject of attacks in right-leaning media and Democrats had suggested her recall was politically motivated.
Over the past few days, the Democratic chairmen of the House Foreign Affairs, Intelligence and Oversight committees have issued subpoenas to Secretary of State Mike Pompeo and Mr Trump's personal lawyer Rudy Giuliani, and scheduled depositions with a series of other current and former officials, as well as associates of Mr Giuliani, as they seek to unearth more evidence of potential wrongdoing by Mr Trump.
The President asked Mr Zelensky during the July call to investigate Mr Biden and his son Hunter, in coordination with US Attorney-General William Barr and Mr Giuliani.
Announcements of more subpoenas and requests for depositions are expected.
The impeachment investigation has cast a pall over Mr Trump's re-election effort.
On Twitter on Tuesday, he repeated his assertion that his call with Mr Zelensky was "perfect", and attacked Ms Pelosi and Representative Adam Schiff, the House Intelligence Committee chairman.
"This is just another Fake News Media, together with their partner, the Democrat Party, Hoax!" the President tweeted.
On Tuesday, Mr Pompeo took to Twitter to address the investigation.
He posted a letter accusing Representative Eliot Engel, the House Foreign Affairs Committee chairman, of requesting depositions as "an attempt to intimidate, bully and treat improperly" State Department employees.