Democratic presidential nominee Joe Biden called President Donald Trump “a fool” after the president claimed that Biden used drugs to sharpen his performance during the Democratic primary debates.

“He’s a fool. The comments were just foolish,” Biden said in a WFLA-TV interview on Tuesday, Sept. 15, according to NBC News.

President Trump, who calls Biden “Sleepy Joe,” has repeatedly challenged the former vice president, 77, to take a drug test ahead of their debate.

During a Fox News interview last week, the president said he believed “there’s probably, possibly, drugs involved” when Biden was on the Democratic debates. “That’s what I hear. I mean, there’s possibly drugs. I don’t know how you can go from being so bad where you can’t even get out a sentence …” President Trump said.

Biden has fueled accusations about his cognitive abilities after piling up a series of blunders this week. On Tuesday, Biden mistakenly confused Iran and Iraq when referring to fallen soldiers, saying, “U.S. troops died in Iran and Afghanistan.”

Additionally, Biden also raised eyebrows when he bungled the Democratic ticket, touting plans under a “Harris-Biden administration.”

“It makes it so much harder for military spouses to find good jobs and build their careers. That has to change,” Biden said. “A Harris-Biden administration is going to relaunch that effort, and keep pushing further to make it easier for military spouses and veterans to find meaningful careers, to ensure teachers know how to support military children in their classrooms, and to improve support for caregivers and survivors, so much more than we do now.”

On the same day, Biden drew criticism after playing the popular song Despacito at a campaign event in Kissimmee, Florida, in an attempt to appeal to Latino voters.

“This is so unbelievably cringe,” tweeted Erielle Davidson, a senior policy analyst at the Jewish Institute for National Security of America.

“What is this all about?” President Trump tweeted.