Former Democratic presidential candidate Bernie Sanders speaks to reporters beside Senate Democratic Leader Chuck Schumer (2nd R) and House Democratic Leader Nancy Pelosi (R), Jan. 4, 2017. Reuters

Vermont Senator Bernie Sanders criticized Hillary Clinton and the Democratic Party Thursday for catering mostly to the rich and elite sectors of society, which he believed led to their electoral downfall, according to an NPR interview.

Sanders, who unsuccessfully ran against Clinton for the Democratic Party's presidential nomination last year, said that the Democrats failed to communicate to voters in rural parts of the country and that the party had neglected its progressive roots to pursue a more privileged agenda. Clinton, who outspent Republican opponent Donald Trump by nearly $500, came up short in electoral college votes, paving the way for a Trump presidency.

"Look, you can't simply go around to wealthy people's homes raising money and expect to win elections. You've got to go out and mix it up and be with ordinary people," Sanders said.

"The Democratic Party swallowed the bait. They became hooked on big money," he added.

Clinton raised a total of $1.4 billion compared to Trump's $932 million. Trump's campaign also saw more small donations, classified as amounts $200 or less, which made up of over a fourth of his contributions. Small donations made up only 16 percent of Clinton's campaign. While competing for the Democratic nomination, Sanders' average donation amount was $27, something he said demonstrated his connection to lower and middle-class voters after receiving $209 million in total campaign contributions.

Sanders ran as a Democrat, but holds office as an independent who identifies with Democratic Socialist politics. In Friday's interview, he said Trump won because his message appealed to "millions of people who have given up on the political process," especially blue-collar workers in crucial swing states such as Michigan, Wisconsin and Pennsylvania. He urged the Democratic Party to "start listening" to these disenfranchised populations and criticized Trump's current initiatives to scale back federal assistance programs.

Clinton, who has spoken infrequently to the public about her loss, told an audience at a December dinner that her loss was due to "unprecedented factors" including an FBI investigation concerning her use of private e-mail servers and hacks that led to the release of private e-mails within the Democratic Party. Clinton blamed the Russian government for perpetrating the leaks, which she said was executed because Russian President Vladimir Putin had "a personal beef" with her. T

he CIA, FBI and President Barack Obama have since condemned what they believe to be Moscow's interference in the election, while Trump and Putin have dismissed these claims.