“This president talks about cognitive capability. He doesn’t seem to be cognitively aware of what’s going on,” the former vice president said during a Tuesday press conference in Wilmington, Delaware.

The remark was in response to a question about recent allegations that Trump ignored intelligence briefings about a possible Russian military scheme to offer bounties to Taliban-linked militia for the killing of American troops in Afghanistan.

“He either reads and/or gets briefed on important issues and he forgets it or he doesn’t think it’s necessary that he needs to know it,” Biden added.

The New York Times recently reported that the intelligence assessment had been included in Trump’s daily briefing in late February. The Associated Press reported this week that top White House officials were aware of the bounty situation as early as 2019.

Trump and White House officials have refuted the allegations. Trump tweeted on Sunday night that the intelligence community didn’t make him aware of the situation because it did not find the reports of Taliban bounty payments to be credible.

Asked to weigh in, Biden said either way it’s an abdication of leadership on Trump’s part. “The idea that he didn’t know, or wasn’t being briefed, that’s a dereliction of duty. And if he was briefed and didn’t do anything, that’s a dereliction of duty.”

Biden later added that he couldn’t wait to debate Trump in the months leading up to the November election. So far the Biden campaign has committed to three debates with the president, while Trump has pushed for four events.

“I can hardly wait to compare my cognitive ability with the cognitive ability of the man I am running against,” Biden said.

The former vice president seems to be turning the tables on the Trump campaign’s ongoing effort to paint Biden as mentally unfit for office. The president has repeatedly said “Sleepy Joe” is too old to be president, even though they are only three years apart in age. Trump just turned 74, while Biden is 77.

Earlier this month, Trump’s 2020 campaign launched a website called “Barely There Biden,” which it said would “detail Joe Biden’s descent into incoherence throughout his third campaign for president.”

The president’s re-election team also released an ad last week depicting Biden as aged and confused. The clip calls him “clearly diminished” and missing some “mental fortitude.”