SOUTH BEND, INDIANA – APRIL 14: South Bend Mayor Pete Buttigieg announces that he will be seeking the Democratic nomination for president during a rally in the old Studebaker car factory on April 14, 2019 in South Bend, Indiana.

Scott Olson | Getty Images

Democratic presidential contender Pete Buttigieg, the mayor of South Bend, Indiana, will return thousands of dollars donated to his campaign by registered federal lobbyists and will not accept such contributions any longer, his campaign said Friday.

Buttigieg faced mounting pressure from his party’s progressive base to disavow lobbyist money. He was the last major Democrat running for president to swear it off.

“Mayor Pete will not be influenced by special-interest money, and we understand that making this promise is an important part of that commitment,” campaign manager Mike Schmuhl wrote in an email to supporters.

The campaign said it will return $30,250 from 39 individuals that it had received so far. It will also bar registered lobbyists from serving as bundlers — a type of major fundraiser.

Like other Democratic presidential campaigns, Buttigieg also rejects money from fossil fuel industry executives and political action committees tied to corporations, a pledge Schmuhl re-iterated in the email to supporters.

“We understand that making this decision and being vocal about our values is important; that the decision means more than just whether or not we are willing to accept money from a specific individual,” Schmuhl wrote.

Buttigieg’s campaign has attracted enthusiasm from a number of top Democratic fundraisers since it launched in late January. One early supporter was Steve Elmendorf, CNBC has reported, a registered lobbyist who raised funds for Hillary Clinton during the last presidential race.

Observers were waiting to see whether former Vice President Joe Biden would take lobbyist money. On Thursday, Biden officially entered the race and his campaign said it will not.

Critics, however, including liberal Democratic contenders Sen. Bernie Sanders of Vermont and Sen. Elizabeth Warren of Massachusetts, have questioned Biden’s attempt to distance himself from K Street.

Hours after entering the race, Biden attended a fundraiser at the home of Comcast executive David Cohen, who oversees the firm’s lobbying arm.

Buttigieg’s campaign has quickly gained steam, ascending from essentially zero name recognition to the top levels of the crowded Democratic field in a matter of weeks.

The campaign raised $7 million in the first quarter of 2019, according to filings submitted to the Federal Election Commission.