The US Congress may be forced into impeachment proceedings against US President Donald Trump.
That is the warning from the US House Intelligence Committee chairman if it is confirmed that Trump pressured Ukraine to investigate Joe Biden.
It has been reported that Trump threatened to cut off military aid to Ukraine if its president did not investigate whether Biden used his position as vice president to help his son.
But Trump insists he has done nothing wrong.
Al Jazeera's Mike Hanna reports from Washington, DC.