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Fossil fuel donations set Democratic primary on fire

A minute or so of cell phone video from an environmental activist has tipped off one of the most heated conflicts of the Democratic primary.

A minute or so of cell phone video from an environmental activist has tipped off one of the most heated conflicts of the Democratic primary, now spilling into its second day as Bernie Sanders’ campaign demands an apology and Hillary Clinton’s camp accuses her rival of lying.

Environmentalist have pressed Clinton to stop accepting donations from people connected to fossil fuel industry on several occasions. But when a Greenpeace activist approached Clinton about the issue Thursday afternoon, the former secretary of state seemed to lose her cool, jabbing her finger and accusing the Sanders campaign of lying about the issue.

RELATED: Clinton lashes out: 'I am so sick of the Sanders campaign lying'

New York City Mayor Bill de Blasio, whose 2013 campaign gave him a national profile as a progressive leader, said Friday that this debate has pushed the Democratic primary over a line. “Up to now, this discussion has been a credit to the party,” de Blasio warned.

De Blasio managed Clinton's 2000 Senate campaign and has endorsed her this year, so he blamed Sanders for inciting questions about donations from oil and gas companies.

“I'm a progressive, and I tell you this one doesn't hold water,” de Blasio said on a conference call organized by the Clinton campaign. “Any suggesting that she is in anyone's pocket on the issue of climate change or another issue is just flat out false and inappropriate.”

He called on Sanders to get his supporters in line and added, “This attack is not becoming of this movement to bring about more progressive change.”

Meanwhile, Sanders campaign manager Jeff Weaver said Friday that Clinton’s campaign started this fight -- and that she is the one who needs to tone it down.

“We did not say she is lying. The secretary did. And I think she probably owes the senator an apology for that. Because the senator is not lying about her record. She obviously doesn’t like it, but that doesn’t make it lying.” Weaver told NBC News' Chuck Todd.

Employees of oil and gas companies have donated about $307,000 to Clinton’s campaign, and $54,000 to Sanders’ campaign. Neither has taken money from political action committee's connected to the industry. For both campaigns, it's a minuscule portion of the total amount of money they have brought in.

Some of Clinton bundlers, however, are also lobbyists who have had ties to oil and gas companies. However, many of those lobbyists represent variety of industries, not just oil and gas. A Clinton ally also noted that she has received money from a former NRA lobbyist, but no one doubts her commitment to gun control.

Clinton’s campaign says Sanders supporters have nothing to point to when they say she's doing the bidding of fossil fuel interests. To the contrary, they say she’s been a champion of clean energy and phasing out fossil fuel.

De Blasio, for instance, noted that just the other week, Clinton suffered a week of bad headlines after saying in Ohio, “We're going to put a lot of coal miners and coal companies out of business.” De Blasio euphemistically called the comment “politically courageous."

Still, Democrats have for years maintained that donations can in and of themselves have a corrupting influence in politics, even if there is no clear quid pro quo. 

Meanwhile, Sen. Barbara Boxer, the top Democrat on the Senate Environment Committee and a Clinton backer, called for peace. “Both Hillary and Bernie accepted donations from fossil fuel workers, and both care deeply about the environment,” she tweeted. “The last thing we need is for the Democratic race, which we have been so proud of, to devolve into GOP-style mudslinging.”