Public hearings are set to get under way next week. Here’s who is scheduled to testify.

Public hearings in US House of Representatives’ impeachment inquiry of President Donald Trump got under way last week, marking a new phase in the probe.

The impeachment inquiry is centred on a July 25 phone call between Trump and Ukrainian President Volodymyr Zelenskyy in which the US president asked the Ukrainian leader to investigate former Vice President Joe Biden, who is also a frontrunner in the 2020 Democratic presidential race and his son, Hunter, who had served on the border of a Ukrainian gas company. The request came as Trump withheld nearly $400m in military aid to Ukraine, prompting speculation that the US president was using the money as leverage for the investigation.

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There has been no evidence of wrongdoing by the Bidens. Trump maintains there was no quid pro quo (Latin for “favour for a favour”) and has labelled the impeachment inquiry a “witch-hunt”.

During the public hearings, lawyers for the committees involved in the investigation will conduct questioning for extended periods of time.

Here’s the schedule* for this week’s public hearings:

Tuesday, November 19

Morning

Jennifer Williams , the special adviser to Vice President Mike Pence for Europe and Russia

, the special adviser to Vice President Mike Pence for Europe and Russia Alexander Vindman, a US Army officer assigned to the National Security Council. Read more about Vindman’s closed-door testimony here.

Afternoon

Kurt Volker, a former US special envoy to Ukraine. Read more about Volker’s closed-door testimony here.

a former US special envoy to Ukraine. Read more about Volker’s closed-door testimony here. Timothy Morrison, a White House aide with the National Security Council

Wednesday, November 20

Morning

Gordon Sondland, the US ambassador to the European Union. Read more about Sondland’s closed-door testimony here.

Afternoon

Laura Cooper , the deputy assistant secretary of defence for Russia, Ukraine and Eurasian affairs

, the deputy assistant secretary of defence for Russia, Ukraine and Eurasian affairs David Hale, undersecretary of state for political affairs at the State Department

Thursday, November 21

Fiona Hill , former National Security Council senior director for Europe and Russia

, former National Security Council senior director for Europe and Russia David Holmes, State Department

Here’s who spoke last week:

Wednesday, November 13 William Taylor , a US career diplomat who serves as the charge d’affaires in the US embassy in Ukraine.

, a US career diplomat who serves as the charge d’affaires in the US embassy in Ukraine. George Kent, deputy assistant secretary of state for Eastern Europe

deputy assistant secretary of state for Eastern Europe Read about their public testimony here. Ambassador William Taylor is escorted by US Capitol Police as he arrives to testify before House committees as part of the Democrats’ impeachment investigation of President Donald Trump [J Scott Applewhite/AP Photo] Friday, November 15 Marie Yovanovitch, former US ambassador to Ukraine. Read more about Yovanovitch’s testimony here.

*Schedule will be updated as hearings are announced