Joe Biden slipped up once again on the campaign trail Saturday, saying he was vice president at the time of the mass shooting at Marjory Stoneman Douglas High School in Parkland, Fla., adding to the number of mishaps that have drawn mockery from his opponents.

The 76-year-old Biden, who left the vice presidency in 2017, was talking about gun violence with reporters in Iowa when he said that “those kids in Parkland came up to see me when I was vice president" after the shooting that left 14 students and three educators dead.

A campaign official told Bloomberg that Biden was thinking of the December 2012 massacre at Sandy Hook Elementary School in Newtown, Conn. that left 20 young children and six staff members dead.

MSNBC ANCHOR DEFENDS BIDEN AFTER LATEST GAFFE, SAYS TRUMP CAMPAIGN 'SEIZED ON A FEW WORDS'

Democratic presidential candidate former Vice President Joe Biden speaks at the Presidential Gun Sense Forum, Saturday, Aug. 10, 2019, in Des Moines, Iowa. (AP Photo/Charlie Neibergall)

The gaffe is the latest in a string of blunders that has dogged the 2020 Democratic frontrunner.

On Thursday, the former vice president told a crowd that "poor kids were just as bright and talented as white kids." After a very brief pause, Biden quickly continued speaking, adding: “Wealthy kids, black kids, Asian kids.”

Earlier this week, Biden mistakenly said the recent mass shootings in El Paso, Texas and Dayton, Ohio took place in Houston and Michigan.

President Trump has tried to seize on Biden's well-publicized gaffes to make the case that he isn't fit to lead the country. On Friday, the president said Biden "is not playing with a full deck" in response to his "poor kids" comments.

Trump also piled on Saturday, asking on Twitter if Biden was fit to be president.

"Joe Biden just said, 'We believe in facts, not truth.' Does anybody really believe he is mentally fit to be president? We are 'playing' in a very big and complicated world. Joe doesn’t have a clue!"

An error occurred while retrieving the Tweet. It might have been deleted.

The tweet appears to refer to Biden's Thursday speech at the Iowa State Fair when he said: “We choose science over fiction. We choose truth over facts.”

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Former Virginia Gov. Terry McAuliffe -- a former chairman of the Democratic National Committee -- said Friday on HBO's "Real Time with Bill Maher" that Biden's occasional mishaps were preferable to the "10,000 lies" he claimed President Trump has told since taking office.