President Trump on Monday attacked former vice president Joe Biden as “another low I.Q. individual,” pointing to comments the Democrat inadvertently made Saturday night suggesting he had already launched a 2020 White House bid.

“Joe Biden got tongue tied over the weekend when he was unable to properly deliver a very simple line about his decision to run for President,” Trump said in a tweet. “Get used to it, another low I.Q. individual!”

Biden, who appears on the cusp of making another White House bid official, seemed to get ahead of himself while speaking at a fundraising dinner for Delaware Democrats about his record.

“I have the most progressive record of anybody running for the United —” he said, before catching himself and saying “anybody who would run” for president.

Biden, 76, has repeatedly pushed back possible announcement dates for what would be his third run for the presidency. He has tapped staffers who would be expected to lead a national campaign, leaving many of his political allies convinced he’ll run. But he has not made those plans official.

A spokesman for Biden did not immediately respond to a request for comment on the president’s tweet.

Trump has said he would welcome a challenge from Biden. During a CBS interview last year, the president said running against Biden would be “a dream,” claiming that Barack Obama “took him out of the garbage heap” to make him his running mate in 2008.

Biden unsuccessfully sought the Democratic presidential nomination in 1988 and in 2008, both times dropping out after poor showings.

That was evidence, Trump said, that Biden “by himself could never do anything.”

David Weigel contributed to this report.