Sen. John McCain (R-Ariz.) appeared to heap more criticism on President Donald Trump during an interview on Sunday, saying it was “wrong” for high-income Americans to dodge the draft during the Vietnam War.

“One aspect of the conflict, by the way, that I will never ever countenance is that we drafted the lowest income level of America and the highest income level found a doctor that would say that they had a bone spur,” McCain said during a segment on the draft that aired on C-SPAN 3 on Sunday. “That is wrong. That is wrong. If we’re going to ask every American to serve, every American should serve.”

While the senator’s comments didn’t directly reference Trump, the president is widely known to have received five deferments from the draft during the Vietnam War, four for education and one for bone spurs in his heels.

The New York Times obtained the president’s Selective Service records last August, and during an interview at the time Trump said the spurs had been “temporary” and “minor” and that over time, they “healed up.”

“They were spurs,” he told the outlet, although he noted that they were “enough of a problem.” He continued: “You know, it was difficult from the long-term walking standpoint.”

TONIGHT - @SenJohnMcCain talks about the Vietnam War's legacy on C-SPAN, at 6 & 10pm ET. pic.twitter.com/WnZT0n8Mcn — American History TV (@cspanhistory) October 22, 2017

McCain served in Vietnam and was a prisoner of war for more than five years after his aircraft was shot down, during which he was tortured and held in solitary confinement.

Trump lambasted the senator during his presidential campaign last year, saying McCain was “not a war hero.”

“I like people that weren’t captured,” he said.

McCain, who was diagnosed with brain cancer in July, has amped up his criticism against the White House and members of his own party in recent months.

Last week, the senator used an acceptance speech for an award honoring his 60-year career in public service to slam what he called “half-baked, spurious nationalism” that had arisen in America following last year’s presidential election.

“We live in a land made of ideals, not ‘blood and soil,’” McCain said during his acceptance of the prestigious Liberty Medal, referencing the Nazi slogan chanted at recent right-wing rallies. “We are the custodians of those ideals at home and their champion abroad. We have done great good in the world. ... We will not thrive in a world where our leadership and ideals are absent. We wouldn’t deserve to.”