At his rally in central Ohio on Saturday night, President Trump took aim at U.S. Sen. Dianne Feinstein, criticizing the longtime member of the Senate Intelligence Committee for reportedly having a suspected Chinese spy on her staff in the past.

“The leader of the Russia investigation, Dianne Feinstein, had a Chinese spy as her driver for 20 years,” Trump said about California’s senior U.S. senator, the Washington Times reported. “And she’s leading the Russian ‘witch hunt.’ Isn’t that something? And then she says to me, ‘What did you know about this and that?’ Give me a break.”

“The leader of the Russia investigation, Dianne Feinstein, had a Chinese spy as her driver for 20 years. And she’s leading the Russian ‘witch hunt.’ Isn’t that something? And then she says to me, ‘What did you know about this and that?’ Give me a break.” — President Donald Trump, at a rally in Ohio on Saturday

The president’s remarks continued a feud that Trump had begun on Twitter on Friday night, when he reacted to reports of the Feinstein story.

“Dianne is the person leading our Nation on ‘Collusion’ with Russia (only done by Dems),” the president tweeted. “Will she now investigate herself?”

Feinstein retaliated with a pair of tweets Saturday.

“The FBI told me 5 years ago it had concerns that China was seeking to recruit an administrative member of my Calif staff (despite no access to sensitive information),” Feinstein wrote in the first message. “I took those concerns seriously, learned the facts and made sure the employee left my office immediately.

“Compare that to your actions: attacking the FBI and refusing the advice of your national security team. SAD! I appreciated then and now the diligent work of our law enforcement and intelligence agencies and acted in the best interests of the country. Give it a try!”

Earlier in the week, Politico and other outlets reported that Feinstein learned from the FBI about five years ago that a staffer in her San Francisco office was suspected of delivering political intelligence, though nothing top secret, to officials at the local Chinese Consulate.

Feinstein was said to have been “mortified” when she learned the news, according to Politico.

The FBI wasn’t able to charge the individual, but Feinstein “forced him to retire,” a source told the San Francisco Chronicle.

In Ohio, Trump used the Feinstein story as an example that other countries besides Russia are engaged in espionage against the United States.

“Not only China, it’s a lot of people,” Trump said, according to the Washington Times. “And we’ve got to stop it. We’ve got to stop meddling, we’ve got to stop everybody from attacking us. But there are a lot. Russia’s there, China’s there. We’re doing well with North Korea, but they’re probably there [spying]. We’ve got to stop everybody.

“And I like Dianne Feinstein. But I don’t like the fact that she had a Chinese spy driving her, and she didn’t know it.”

Earlier this year, Trump blasted “sneaky Dianne Feinstein” after the Democrat released the transcript of a congressional interview with the co-founder of Fusion GPS, the firm behind the anti-Trump dossier, claiming the move was “possibly” illegal.

“The fact that Sneaky Dianne Feinstein, who has on numerous occasions stated that collusion between Trump/Russia has not been found, would release testimony in such an underhanded and possibly illegal way, totally without authorization, is a disgrace. Must have tough Primary!” Trump tweeted in January.

Trump’s visit Saturday to Lewis Center, Ohio, was mostly about supporting state Sen. Troy Balderson, a Republican looking to win a special election for a U.S. House seat this coming Tuesday.

Fox News’ Lukas Mikelionis and Brooke Singman and the Associated Press contributed to this story.