Republican presidential nominee Donald Trump Donald John TrumpREAD: Cohen testimony alleges Trump knew Stone talked with WikiLeaks about DNC emails Trump urges North Korea to denuclearize ahead of summit Venezuela's Maduro says he fears 'bad' people around Trump MORE on Thursday released an Instagram video that slams Bernie Sanders Bernard (Bernie) SandersSenate Dems seek to turn tables on GOP in climate change fight Bernie Sanders Town Hall finishes third in cable news race, draws 1.4 million viewers Woman to undecided Biden: 'Just say yes' to 2020 bid MORE as a quitter who gave up on his political movement.

The video uses footage from the campaign to suggest Sanders can't handle high-pressure situations but Trump can. It comes as Trump seeks to win over supporters of Sanders, who tend to be liberal but many of whom are not fans of Democratic presidential nominee Hillary Clinton Hillary Diane Rodham ClintonREAD: Cohen testimony alleges Trump knew Stone talked with WikiLeaks about DNC emails County GOP in Minnesota shares image comparing Sanders to Hitler Holder: 'Time to make the Electoral College a vestige of the past' MORE.

ADVERTISEMENT

Trump captioned the Instagram post: "Bernie caved!"

"I say these words to you tonight," Trump said in footage from the video taken from last week's Republican National Convention in Cleveland.

"I am with you, I will fight for you, and I will win for you."

In mocking Sanders, the video says that "being president, you need to handle pressure."

It then shows a clip of the Vermont senator's speech to an audience at an event on the margins of the Democratic National Convention this week, during which he said the country needs to elect Clinton and Sen. Tim Kaine Timothy (Tim) Michael KaineTrump claims Democrats ‘don’t mind executing babies after birth’ after blocked abortion bill Democrats block abortion bill in Senate Trump unleashing digital juggernaut ahead of 2020 MORE (D-Va.), her running mate, to the White House. Sanders was booed when he mentioned Clinton's name.

"Some candidates cannot handle the pressure," the video then states.

The video also includes a clip from August of a Sanders rally where protesters with the Black Lives Matter movement stormed the stage and took the microphone from Sanders.

Trump has repeatedly criticized Sanders, calling the Vermont senator "exhausted" and saying he just wants to "go home to bed." He has said that Sanders "sold out" to Clinton, calling the time and effort he put into his campaign a waste.