Rep. Alexandria Ocasio-Cortez, D-N.Y., spoke out Saturday against a Democratic Congressional Campaign Committee plan to help incumbents fight off challengers in the Democratic primary.

“The @DCCC’s new rule to blacklist+boycott anyone who does business w/ primary challengers is extremely divisive & harmful to the party,” Ocasio-Cortez said on Twitter. “My recommendation, if you’re a small-dollar donor: pause your donations to DCCC & give directly to swing candidates instead.”

Ocasio-Cortez was elected last fall as part of a Democratic freshman class which included the most women ever in Congress and many progressive representatives. She defeated longtime Rep. Joe Crowley, who was chairman of the House Democratic Caucus, in their primary.

The new policy from the campaign arm for House Democrats targets primary challengers' ability to raise funds and build up their campaign organization, saying specifically that their "core mission" is to protect incumbents. “[T]he DCCC will not conduct business with, nor recommend to any of its targeted campaigns, any consultant that works with an opponent of a sitting Member of the House Democratic Caucus,” the DCCC said in their statement on the policy.

A number of left-wing Democrats are dismayed by the policy, including Rep. Ro Khanna, D-Calif., the vice chairwoman of the Congressional Progressive Caucus, who called it "totally tone-deaf to the grassroots activists across our nation."

Rep. Ayanna Pressley D-Mass., who also ran as a progressive challenger against an establishment candidate, also spoke out against the DCCC’s new rule in a long Twitter thread.

“If the DCCC enacts this policy to blacklist vendors who work with challengers, we risk undermining an entire universe of potential candidates and vendors - especially women and people of color - whose ideas, energy, and innovation need a place in our party,” Pressley said.

“So, let me be clear: I believe fiercely in the potential of our party, but we cannot credibly lay claim to prioritizing diversity & inclusion when institutions like the DCCC implement policies that threaten to silence new voices and historically marginalized communities,” she added.

The fight over the new DCC policy is the latest example of House Speaker Nancy Pelosi, D-Calif., and the Democratic establishment struggling to get a handle on the members and demands of the young, progressive wing of her party.

Other recent clashes have centered on the Green New Deal from Ocasio-Cortez and talk of impeaching President Trump.