Donald Trump's longtime role as an on-again-off-again cheerleader for Bernie Sanders came to an abrupt end Tuesday as Sanders endorsed his former rival Hillary Clinton, with Trump accusing Sanders of 'selling out.'

'Bernie Sanders endorsing Crooked Hillary Clinton is like Occupy Wall Street endorsing Goldman Sachs, Trump tweeted in one of many broadsides at Sanders, who sometimes seemed to have a public kinship with Trump because of the way each ran campaigns that challenged party orthodoxy.

'I am somewhat surprised that Bernie Sanders was not true to himself and his supporters. They are not happy that he is selling out!' tweeted Trump.

Trump has long tried to lure some of Sanders' anti-trade backers into his orbit, sprinkling compliments on the Vermont Sanders even while mocking him as 'Crazy Bernie.'

Scroll down for video

Donald Trump scolded Bernie Sanders for 'selling out' and endorsing Hillary Clinton on Tuesday

Trump pointed to the trade issue in one of his tweets. Sanders noted during the primaries that Clinton had called the Trans Pacific Partnership trade deal the 'gold standard,' though she ultimately became a critic of the deal as Sanders ran at her from the left.

'Bernie sanders has abandoned his supporters by endorsing pro-war pro-TPP pro-Wall Street Crooked Hillary Clinton,' Trump wrote.

Sanders notably didn't mention trade during his generally full-throated praise of Clinton, whom he lauded as 'far and away the best candidate' Tuesday at a joint appearance in New Hampshire, as Clinton nodded constantly in agreement.

Clinton herself brought it up, and singled out 'bad trade deals and unfair trade practices including the Trans-Pacific Partnership,' an agreement she spoke about favorably when she was secretary of state but has now criticized as inadequate.

In what may be the lowest blow from Trump's vantage point, he called Sanders a bad negotiator.

'Bernie Sanders, who has lost most of his leverage, has totally sold out to Crooked Hillary Clinton. He will endorse her today - fans angry!' Trump wrote.

ALL IS FORGIVEN: Sanders called Clinton 'far and away the best candidate'

Trump previously praised Sanders at times, but wrote Tuesday that he wasn't 'true to himself and his supporters'

Being a bad negotiator is a major defect in Trump's view, and Sanders may have blundered by holding out too long and getting creamed in the California primary

Trump took a dig and brought up Goldman Sachs – the same firm Sanders mentioned when calling for Clinton to release transcripts of her paid speeches

Trump made explicit appeals to Sanders' supporters

PEOPLE FIRST: Trump wrote he'd welcome Bernie's supporters 'with open arms,' though many will be unlikely to back a real estate mogul who wants to cut taxes

Trump even tried to harness some 'people power' from Sanders holdouts, though his ideology shares far more with Hillary Clinton than with Trump.

'To all the Bernie voters who want to stop bad trade deals & global special interests, we welcome you with open arms. People first,' Trump wrote.

The Trump campaign sent out a release by advisor Stephen Miller headlined: 'BERNIE IS NOW OFFICIALLY PART OF A RIGGED SYSTEM.'

"Today, Bernie Sanders will be endorsing one of the most pro-war, pro-wall street, and pro-off shoring candidates in the history of the Democratic Party, went the Trump release.

'The candidate who ran against special interests is endorsing the candidate who embodies special interests. The candidate who ran against TPP is endorsing the candidate who helped draft the TPP. The candidate who ran in opposition to globalization is running against the candidate who has led the push for globalization,' he wrote.

Trump occasionally praised Sanders during the primaries, particularly when he went after rival Hillary Clinton.

In April, Trump said of Sanders, "He said some things about her that were so incredible – incredible – and so incredibly bad,” then said Sanders had "been telling the truth."

Trump also frequently pointed to the size of Sanders' crowds, though he always said that his own crowds were larger.