Joe Biden fired back at President Donald Trump on Saturday for reportedly urging the Ukrainian government to probe into the shadowy ties his son has to one of its largest energy companies.

The former vice president, who for months has refused to discuss the business dealings of his youngest son, Hunter Biden, has undertaken with foreign governments, accused Trump of misusing his authority while attending the Polk County Steak Fry in Des Moines, Iowa.

“This appears to be an overwhelming abuse of power,” Biden told reporters at the event. “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 … this is outrageous.”

The former vice president’s comments come one day after the Wall Street Journal reported that Trump allegedly asked Ukrainian President Volodymyr Zelensky to look into Hunter Biden’s ties to Burisma Holdings.

The younger Biden joined the natural gas company’s board of directors in April 2014, where he was purportedly paid more $83,000 a month, despite having no prior background in the energy industry. At the same time, the then-vice president was the Obama administration’s point-man on Ukraine in the wake of Russia’s annexation of Crimea.

More troubling is the fact that at the time of Hunter Biden’s appointment, Burisma was actively seeking to curry favor with western leaders, especially those in the U.S., after its business practices had come under scrutiny.

In April of 2014 — the same month that Hunter Biden joined Burisma’s board of directors — the government of Great Britain froze accounts belonging to the company’s founder, Mykola Zlochevsky, under suspicion of money laundering. Zlochevsky, a former Ukraininan minister of natural resources, would later be accused of corruption for using his official position to issue oil and gas licenses to companies under his control.

The controversy surrounding Hunter Biden, Burisma, and Zlochvesky only grew more muddy in 2016 when the then-vice president pressured Ukraine to fire the prosecutor general, Viktor Shokin, overseeing the investigation into the company. Officially, Biden claimed the threat to withhold more than $1 billion in U.S. to Ukraine came from President Barack Obama, who was worried Shokin had lost credibility with western leaders. Regardless of the reasoning, Shokin’s successor closed the investigation into Burisma and Zchlovesky, allowing the oligarch to return to the country after having fled in 2014.

Biden even bragged about the effectiveness of his threat during an event at the Council of Foreign Relations in 2018.

“I looked at them and said, ‘I’m leaving in six hours. If the prosecutor is not fired, you’re not getting the money,'” Biden said. “Well, son of a bitch. He got fired. And they put in place someone who was solid at the time.”

The former vice president, however, did not mention the context of his or his son’s dealing with Ukraine while campaigning in Iowa on Saturday. Instead, Biden swiveled between attacking Trump for allegedly asking Ukrainian authorities to investigate the situation to denouncing the media for covering the story.

“You should be looking at Trump,” Biden told reporters when discussing the topic. “Everybody looked at this and everybody who’s looked at it said there’s nothing there. Ask the right question.”

As Peter Schweizer, a contributing editor at Breitbart News and the author of a book detailing Hunter Biden’s ties to both China and Ukraine, noted on Friday, the former vice president’s line of attack shows he wants “the issue to go away.”

“The Bidens are not disputing that he got paid all this money,” Schweizer told Breitbart News Tonight. “They’re not disputing that Hunter Biden had no background in this area. They just simply want the issue to go away, and what apparently President Trump did was have a conversation with the now-Ukrainian president, saying, ‘You need to investigate this. I think you need to investigate this,’ and that’s something we’ve been calling for for a long time.”