Democratic candidate Bernie Sanders addresses his supporters at a rally in Anaheim, California on May 24. | Getty Sanders warns Democrats of Trump, Brexit fallout

Sen. Bernie Sanders is sending a warning sign to Democrats.

Following the United Kingdom's vote to leave the European Union, Sanders wrote in an op-ed in The New York Times published Tuesday that Democrats should be increasingly worried about Donald Trump’s chances to win the presidency.


"The notion that Donald Trump could benefit from the same forces that gave the Leave proponents a majority in Britain should sound an alarm for the Democratic Party in the United States," he wrote.

Sanders remarked upon "[m]illions of American voters, like the Leave supporters, [who] are understandably angry and frustrated by the economic forces that are destroying the middle class."

"In this pivotal moment, the Democratic Party and a new Democratic president need to make clear that we stand with those who are struggling and who have been left behind," Sanders continued. "We must create national and global economies that work for all, and not a handful of billionaires."

Sanders has not dropped out of the Democratic primary race, but Hillary Clinton has secured the necessary number of delegates to win the nomination, and he has vowed to do whatever it takes to make sure Trump will not be the next president.

The Vermont senator, however, did not mention Clinton in the op-ed. Instead, he referenced his signature policies – increasing minimum wage and tuition-free college – and blasted Trump.

“We do not need change based on the demagogy, bigotry and anti-immigrant sentiment that punctuated so much of the Leave campaign’s rhetoric — and is central to Donald J. Trump’s message,” he wrote.