Republican Utah Sen. Mitt Romney said that if President Trump asked Ukrainian officials to investigate former Vice President Joe Biden, it would be "troubling in the extreme."

After reports of a complaint filed by an intelligence community whistleblower, details surfaced of a conversation in which Trump allegedly urged Ukrainian officials to dig into both Biden and his son, Hunter, for his business dealings there.

If the President asked or pressured Ukraine’s president to investigate his political rival, either directly or through his personal attorney, it would be troubling in the extreme. Critical for the facts to come out. — Mitt Romney (@MittRomney) September 22, 2019

"If the President asked or pressured Ukraine’s president to investigate his political rival, either directly or through his personal attorney, it would be troubling in the extreme," Romney tweeted Sunday afternoon. "Critical for the facts to come out."

Trump, who previously called the whistleblower "partisan" despite not knowing the person's identity, reiterated his defense while speaking to reporters Sunday morning. He said there was no "quid pro quo" involved in the talks with the Ukrainian president, and he called the conversation in question a "perfect conversation."