President Donald Trump speaking on the phone, surrounded by his top White House aides. Drew Angerer/Getty Images Breitbart, the website that has fervently supported President Donald Trump's campaign and nascent presidency, signaled this week that its brief cease-fire with the establishment wing of the administration may have come to an end.

The reliably pro-Trump website has lately been reluctant to skewer former Republican National Committee members who now work inside the Trump administration, such as Chief of Staff Reince Priebus and press secretary Sean Spicer.

But that appeared to change on Tuesday, when Breitbart savaged House Speaker Paul Ryan's proposal, which Trump supports, to repeal and replace the Affordable Care Act, better known as Obamacare. The website deemed it "Obamacare 2.0" and told its readers the legislation "gives illegal aliens healthcare through identity fraud" and amounted to "GOP welfare entitlement."

An additional story by Matthew Boyle, the website's Washington editor, went after Spicer for "inaccurately" saying the bill "fully repeals Obamacare."

"We are Breitbart," Boyle wrote in a Slack conversation about his story, according to a screenshot obtained by Business Insider. "This is war."

Boyle added: "There are no sacred cows in war."

Previously, when Boyle published an extremely critical story about Priebus, he was scolded by Stephen Bannon, Breitbart's former chairman and current White House chief strategist, two sources with knowledge of the situation told Business Insider.

Bannon was angry because he and Priebus were portraying themselves in the press as friends and allies — a narrative almost no one bought — and political observers still connected Breitbart's coverage to him. To many, it looked as though Bannon had ordered the attack, though the sources said the story blindsided him.

According to the two sources, Bannon was so furious that he phoned Boyle after the story was published and unloaded on him. Boyle hadn't sought to notify Bannon he was publishing the story in advance, the sources said.

Bannon further aggravated Boyle that week when he instructed him not to publish additional articles critical of Priebus, prompting the Washington editor to tell others that Bannon had betrayed Breitbart and was guilty of "treason," according to a source.

When tension between the two reached a fever pitch, senior White House officials aimed to placate Boyle by offering him access to key staffers, two sources said.

Spicer was made available to Boyle for a Sirius XM radio interview, along with Katie Walsh, a deputy chief of staff. Boyle was later granted a brief sit-down interview with Trump.

But the honeymoon phase appeared to end on Tuesday, with Breitbart largely seeking to place responsibility for the repeal-and-replace legislation on establishment GOP figures, despite Trump's support.

"They thought they could satisfy Boyle by giving him a one-on-one interview with Trump," a source said. "But the thing about Boyle is you can't stop him. You can't control him."

Neither Bannon nor Breitbart responded to requests for comment.