The White House is preparing to release a whistleblower complaint reportedly concerning a phone call President Donald Trump had with his Ukrainian counterpart, an administration official said on Tuesday.

The White House will also most likely allow the whistleblower, a member of the US intelligence community, to meet with congressional investigators, said the official, who spoke on condition of anonymity.

US House of Representatives’ committees are investigating reports Trump pressured Ukraine’s president in a July call to launch a probe of Democratic presidential candidate Joe Biden and his son.