With a slip of the tongue, Donald Trump suggested Monday that President Barack Obama was not his president.

“I agree with her on one thing: The single greatest problem the world has is nuclear armament, nuclear weapons ― not global warming like you think and your president thinks,” he said.

Trump has repeatedly questioned Obama’s legitimacy as president by suggesting that Obama was not born in the United States.

Dan Pfeiffer, a former top aide to Obama, brushed off the comment.

It’s cool Donald, he didn’t want to be your president anyway

— Dan Pfeiffer (@danpfeiffer) September 27, 2016

Several people took to Twitter to call out the outrageousness of Trump’s claim.

He’s OUR president, you pathetic little man.

— olivia wilde (@oliviawilde) September 27, 2016

“your president?” He’s *OUR president, bro. #DebateNight

— NE-YO (@NeYoCompound) September 27, 2016

“Your President…?” I peeped that Trump. @BarackObama is YOUR President u racist ignoramus. Must drive u nuts…#debate2016 #DebateNight ✊🏿✊🏿

— Sean Patrick Thomas (@sean_p_thomas) September 27, 2016

“Your president?” He’s OUR president.. youre included trump #debatenight

— Katie Stevens (@thekatiestevens) September 27, 2016

Trump addressed the comments in the spin room after the debate, saying Obama was “everybody’s president.”

.@realDonaldTrump, when asked about “your president” remark: “He’s everybody’s president.” https://t.co/chpO11aZqc pic.twitter.com/2i6wWzglq0

— CBS News (@CBSNews) September 27, 2016