On Thursday, President Donald Trump held a mass rally, featuring crowds of people with no masks, in Pennsylvania where he ridiculed Democratic nominee Joe Bidens decision to wear a mask.

While Trump urged rally attendees to vote in-person, he also drew attention to Biden’s diligent mask-wearing. Trump commented that Biden’s mask-wearing gives the presidential candidate a “sense of security.”

Despite the U.S. leading with the world’s largest number of COVID-19 cases, Trump claimed that he has never seen another man that “likes masks as much as” Biden. Trump continued to mock Biden. “If I were a psychiatrist, I’d say this guy has some big issues,” he said.

In May, the president poked fun at Biden’s mask-wearing at a Memorial Day ceremony.

Biden clapped back at Trump by calling the president a “fool.” In response to the mockery, he said Trump’s refusal to wear a mask and “macho-stuff” costs people’s lives. “Presidents are supposed to lead, not engage folly and be falsely masculine,” he said.

The exchange came after Trump’s tweet in June where he shared a picture of himself in a mask calling it “patriotic.”

Trump is expected to visit North Carolina, Minnesota and Ohio the following week for more of his ‘Make America Great Again’ events.