Ukraine has asked the FBI in the United States for help to investigate a suspected cyberattack by Russian military hackers on Burisma, an energy company caught up in the impeachment of US President Donald Trump.
The US House of Representatives will vote on a resolution to formalize the impeachment inquiry into President Donald Trump Thursday, which will set rules for the investigation going forward. But what's happened in the inquiry so far? The World looks back at some key moments.
As part of his Thursday testimony to members of the US House of Representatives, former US envoy to Ukraine Kurt Volker turned over text messages between himself, diplomats in Kyiv and others involved with Ukraine, including President Donald Trump's personal attorney, Rudy Giuliani, who played a major part in the administration's dealing with Kyiv.