(CNN) Joe Biden accused Donald Trump of abusing the power of his presidency in urging the Ukrainian President to investigate Biden's son, Hunter, to smear his presidential campaign, angrily calling on Congress to investigate Trump's contact with the foreign leader.

"This appears to be an overwhelming abuse of power to get on the phone with a foreign leader who is looking for help from the United States and ask about me and imply things if that's what happened, that appears to be what happened ... This is outrageous," the former vice president and 2020 Democratic candidate told reporters on Saturday before attending the Polk County Democrats Steak Fry in Des Moines, Iowa.

Biden's comments come following news that Trump pressed Ukrainian President Vologymyr Zelensky in a July 25 phone call to investigate Hunter Biden, according to a person familiar with the situation. Trump has defended the call, dubbing criticism of it a "Ukraine Witch Hunt."

There is no evidence of wrongdoing by either Joe or Hunter Biden.

Speaking to local media Saturday, Ukrainian Foreign Minister Vadym Prystaiko said he didn't think Trump had tried pressuring Zelensky during the July call, but he stopped short of saying the subject of Biden's son wasn't raised.

Read More