The microphone of Republican vice-presidential candidate JD Vance was muted Tuesday night during a debate when he sought to dispute an effort by moderators to fact-check his claims about immigration.

A moderator suggested the microphone of Vance’s Democratic rival, Tim Walz, was also cut off.

The moment unfolded after Vance, an Ohio senator, and Walz, the Minnesota governor, sparred over the situation in Springfield, Ohio. Vance and the GOP presidential nominee Donald Trump have amplified false claims that Haitian immigrants in Springfield are eating pets and are in the country illegally.

“Just to clarify for our viewers, Springfield, Ohio, does have a large number of Haitian migrants who have legal status, temporary protected status,” moderator Margaret Brennan said.

Brennan’s comment prompted a rebuke from Vance, who said: “The rules were that you guys weren’t going to fact-check, and since you’re fact-checking me, I think it’s important to say what’s actually going on.”

Vance went on to try to explain his position, but before long, the volume of Vance’s voice was audibly lower and distant.

“Gentlemen, the audience can’t hear you because your mics are cut,” Brennan said.

The decision quickly angered Republicans. Trump expressed outrage on his Truth Social platform, saying Brennan “cut off JD’s mic to stop him from correcting her!”

Going into the debate, CBS warned that it could cut off the candidates’ microphones.

“CBS News reserves the right to mute the candidates’ microphones, but otherwise, they will be hot,” the network said.

The muting of microphones was a contentious issue in the lead-up to Trump’s debate last month with Vice President Kamala Harris. The Harris campaign wanted microphones to remain hot, while Trump’s campaign successfully pushed to keep the rules from a previous CNN debate where microphones were muted when it was not a candidate’s turn to speak.