A prominent Young Democrats member has stepped down from her position over claims she experienced bullying from "Bernie Bros", a name given to Bernie Sanders' supporters.

Lindy Li was the treasurer for Pennsylvania Young Democrats, but it was announced on Monday by the organisation's president that he had accepted her resignation.

"Tonight I accepted the resignation of our Treasurer and am proud to appoint Rob Collini to the post & announce his confirmation by the PAYD Executive Committee," President TJ DeLuca wrote in a tweet on the organisation's page.

Ms Li, who's running to be a convention delegate for former Vice President Joe Biden, is a vocal critic of Mr Sanders on her Twitter page, often condemening his socialist position within the party. Her critiques gained notice from some of the Vermont senator's supporters, and she claims this criticism encouraged the Pennsylvania Young Democrats to force her to resign, the Philadelphia Inquirer reports.

"This is like Bernie Bro behavior in real life," Ms Li told the newspaper, referencing "aggressive" attacks online. "I wasn't always like this. They drove me to this."

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Previously, she shared an image of herself with Mr Sanders in May 2018. She praised the senator at the time, but her opinions have since changed. Her Twitter platform is now largely used to show support for Democratic candidate Mr Biden and criticise Mr Sanders.

Mr DeLuca, who was elected president of the Pennsylvania Young Democrats last month, shared a different side as to why the organisation asked for her resignation. He told the Philadelphia Inquirer many state Democratic Party officials raised concerns over what was shared on Ms Li's Twitter page.

Former Young Democrat treasurer Lindy Li (pictured with Joe Biden) claims she was ousted for her anti-Bernie Sanders tweets (Lindy Li/Twitter)

He reportedly contacted her to discuss her profile, but she would only respond to emails and text messages instead of agreeing to meet in person, he said.

"Lindy is putting that pressure on herself," Mr DeLuca said. "She said she would rather resign than talk to me about her Twitter account."

One recent tweet Ms Li shared was a video of Mr Sanders from his visit to Russia, then part of the Soviet Union, in 1988. The clip shows him heaping praise on to the country.

"#BernieSanders lavishes praise on Communist Russia, preferring the Soviet Union to the American way of life," Ms Li wrote alongside the clip.

Another critical tweet read: "#BernieSanders, who praised Communist regimes and joined a socialist party that took Iran's side during the hostage crisis, is a grave risk to American democracy. Get at me, #BernieBros. Do what you do best: excel in hate."

Ms Li sparked critiscim last month for also reweeting a tweet that called Mr Sander's a "self-hating Jew". She later deleted the retweet and released an apology, which she now says was an action encouraged by her former organisation. The apology has since been deleted.

"I have spent hours over the phone with TJ discussing my tweets," Ms Li said. "I had nothing left to say and wasn’t going to censor myself to make the Sanders' supporters in our group happy."