Three Democratic-led House Committees issued subpoenas on Friday for Secretary of State Mike Pompeo, seeking to compel him to hand over documents concerning contact with the government of Ukraine.

The House Foreign Affairs, Intelligence and Oversight Committees also scheduled depositions for five State Department officials over the next two weeks.

They include former Ambassador to Ukraine Marie Yovanovitch, who was fired by Team Trump earlier this year; Ambassador Kurt Volker, the special representative for Ukraine; and European Union Ambassador Gordon Sondland.

The subpoenas are part of the Democratic-led House’s impeachment proceedings initiated after a whistleblower alleged that President Trump used the influence of his office to persuade Ukraine to investigate his potential 2020 election foe Joe Biden and his son, Hunter Biden.

Trump has denied any wrongdoing.