Rep. Martha McSally, R-Ariz., who is running for U.S. Senate in Arizona, claimed Monday evening that her opponent Rep. Kyrsten Sinema, D-Ariz., committed “treason," reacting to a 15-year-old radio interview that recently surfaced in which Sinema protested the Iraq and Afghanistan wars.

“While we were in harms way, she was protesting our troops in a pink tutu,” McSally, an Air Force veteran, said during a debate with Sinema. “I want to ask right now whether you’re going to apologize to the veterans and me for saying it’s okay to commit treason."

Sinema responded by saying McSally was using “ridiculous attacks and trying to smear my campaign.”

CNN reported last month that Sinema, who organized anti-war rallies as an anti-war activist in the early 2000s, indicated she would be “fine” with Americans joining the Taliban.

"By me, as an individual, if I want to go fight in the Taliban army, I go over there and I'm fighting for the Taliban,” libertarian activist Ernest Hancock said during a radio interview with Sinema in 2003. “I'm saying that's a personal decision ... "

"Fine," Sinema responded, "I don't care if you want to do that, go ahead."

A spokesperson for Sinema’s campaign Helen Hare told CNN that Sinema’s response was “clearly offhand and an effort to get back on the topic of why she opposed the war.”

Sinema and McSally will go against each other in the 2018 midterm election next month to replace outgoing Republican Sen. Jeff Flake.