Trump spoke to his experience seeing the work of firemen and police in New York during the Sept. 11 attacks during a campaign rally in Buffalo, New York Monday.

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But The Daily Beast reported that Trump made a glaring error during his previously prepared campaign speech.

“I was down there, and I watched our police and our fireman, down there on 7/11, down at the World Trade Center right after it came down,” Trump said. I saw the bravest people I’ve ever seen, including the construction workers, including every person down there.”

Trump said "7/11" when he meant to say, "9/11."

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The flub seemed to go ignored by those in the audience.

Trump did not acknowledge or correct his mistake, either.

Twitter didn't miss the mistake, however, and made a few jokes:

Trump went on to touch on "New York values," as a retort to remarks Republican presidential candidate Ted Cruz initially said in January.

The phrase has been used repeatedly by Trump and Cruz as they increase attacks ahead of more primaries.