U.S. Rep. Devin Nunes is suing CNN for $435 million over a report that an associate of Rudy Giuliani, President Donald Trump’s personal lawyer, claimed Nunes had met with a former Ukrainian official last year to dig up dirt on former Vice President Joe Biden.

Nunes, a California Republican, filed the defamation lawsuit Tuesday in federal court in the Eastern District of Virginia.

CNN reported last month that an attorney for Lev Parnas — a Soviet-born associate of Giuliani who has been charged with making illegal campaign contributions using foreign money — said his client had been told by former Ukrainian Prosecutor General Victor Shokin that he had met with Nunes in Vienna, Austria, last December.

Shokin had been ousted by the nation’s Parliament in 2016 under pressure from the United States and other Western nations that said he was ignoring corruption.

The attorney, Joseph Bondy, said Parnas was willing to testify under oath before Congress that the meeting was to discuss digging up dirt on Biden, a potential foe of Trump in the 2020 presidential election. Parnas said he had been in contact with Nunes to connect him with Ukrainians who could help him find such information.

Nunes disputed the report, telling the right-wing news site Breitbart that the story was “demonstrably false and scandalous.”

The lawsuit calls CNN’s story a “hit piece” and says the network must be held accountable.

“CNN is the mother of fake news,” the lawsuit says. “It is the least trusted name. CNN is eroding the fabric of America, proselytizing, sowing distrust and disharmony.”

Nunes says that he did not travel to Vienna, or anywhere else in Austria, in 2018 — he was in Libya and Malta around the time of the alleged meeting, he says. The lawsuit also says that Nunes has never met Shokin and was not in contact with Parnas last December.

CNN has not commented on the lawsuit.

The Associated Press contributed to this report.