White House spokesperson Sean Spicer tried to pick another fight with the media on Monday — and the media fought back. When Spicer called ProPublica, a nonpartisan, nonprofit investigative journalism outlet, a “left-wing blog,” the organization took the fight to Twitter.

Appropriately for a group that’s known for its document-based reporting, ProPublica showed its receipts.

Here’s how the fight started: During Monday’s press briefing, Politico’s Matthew Nussbaum asked Spicer about a ProPublica report from earlier in the day that revealed that President Donald Trump now can withdraw money from his businesses without disclosing it.

After facing much pressure to distance himself from his businesses throughout his campaign and following his election, Trump before his inauguration put his two adult sons in charge, an arrangement the president called a “blind trust” even though it was anything but. As Derek Kravitz and Al Shaw of ProPublica reported, however, the trust’s documents were amended in February to allow for Trump’s sons to withdraw funds and give them to Trump whenever they “deem appropriate.”

Spicer, in his characteristically combative tone, attacked the reporter asking the question, the article, and the news organization itself:

I think that you just went and started to say, “This change was made.” I'm not aware that there was any change. Just because a left-wing blog makes the point of something changing doesn’t mean it actually happened. I'm not aware that there was ever a change in the trust. And the idea that the president is withdrawing money at some point is exactly the purpose of what the trust — why a trust is set up regardless of an individual.

In response, ProPublica took to Twitter to deliver a 15-tweet thread defending its reporting. “So @seanspicer just called us a ‘left-wing blog.’ Since we’re actually in the biz of facts, we figured we’d respond w/ a few,” the tweets began. (Vox has partnered with ProPublica on some reporting projects but wasn’t involved in the investigation into Trump’s businesses.)

1/ So @seanspicer just called us a “left-wing blog.” Since we’re actually in the biz of facts, we figured we’d respond w/ a few... — ProPublica (@ProPublica) April 3, 2017

Regardless of whether Spicer is “aware” of it, the trust documents were amended to allow for the withdrawals. In its reporting and tweets, ProPublica linked to the documents themselves and to screenshots of the newly added clause.

ProPublica then explained how before it published the article, it reached out to the Trump Organization seeking comment, but “the Trump Organization did not answer detailed questions about the trust.”

.@seanspicer 5/ We do no-surprises journalism. We told the Trump Org & WH what we knew and gave them time to explain.They didn’t. https://t.co/pYfcdEp64W pic.twitter.com/paZfZWr4W1 — ProPublica (@ProPublica) April 3, 2017

ProPublica went on to demonstrate how over the years it has produced reporting critical of both Republicans and Democrats. “Our job always has been and will be holding *all* those in power accountable,” ProPublica wrote, providing links to various stories its reporters have written critical of the Obama administration.

Spicer’s denial and pushback in the briefing is just the latest example of a Trump administration official responding to a news article by trying to discredit the press, rather than defending its own actions. Trump’s war on the media — which he has repeatedly dubbed the “enemy of the people” — is strategic. As Vox’s Andrew Prokop explained, by attacking the press, Trump can attempt to shift attention away from his legislative failures and continuing scandals. The media becomes an easy target for Trump to jump on any time things seem to be going south.

With its tweetstorm, however, ProPublica was able to call out Spicer for his evasions in a highly public environment; as of Tuesday morning, the thread had amassed 20,000 retweets.

1/ So @seanspicer just called us a “left-wing blog.” Since we’re actually in the biz of facts, we figured we’d respond w/ a few... — ProPublica (@ProPublica) April 3, 2017

.@seanspicer 2/ @seanspicer was trying to knock our story that Trump’s trust doc was revised to say he can take $ frm biz anytime https://t.co/xcohyMmoRc — ProPublica (@ProPublica) April 3, 2017

.@seanspicer 5/ We do no-surprises journalism. We told the Trump Org & WH what we knew and gave them time to explain.They didn’t. https://t.co/pYfcdEp64W pic.twitter.com/paZfZWr4W1 — ProPublica (@ProPublica) April 3, 2017

.@seanspicer 6/ What we do is hold people in power accountable, no matter who they are, or what names they call us. We do it with facts. Like... — ProPublica (@ProPublica) April 3, 2017

.@seanspicer 7/ The fact that Tom Price bought drug company stock same day he pushed policy that could help the company. https://t.co/nica3s6oi1 — ProPublica (@ProPublica) April 3, 2017

.@seanspicer 8/ The fact that Trump has quietly installed officials across the government to be his eyes and ears: https://t.co/UhSNXaGwBH — ProPublica (@ProPublica) April 3, 2017

.@seanspicer 9/ The fact that Jared Kushner isn’t actually separating himself from his business empire: https://t.co/ZNFNVOkfdL — ProPublica (@ProPublica) April 3, 2017

.@seanspicer 10/ Or the fact that 5 top Trump officials have made false statements to Congress:https://t.co/xQGhQwEWaF — ProPublica (@ProPublica) April 3, 2017

.@seanspicer 11/ And yes, our job always has been and will be holding *all* those in power accountable. — ProPublica (@ProPublica) April 3, 2017

.@seanspicer 12/ So, we wrote about fact that Obama caved to big banks and didn’t deliver on his promises to help homeowners: https://t.co/DnhEUzJIoP — ProPublica (@ProPublica) April 3, 2017

.@seanspicer 13/ We wrote about former Obama officials lobbying to push through a merger that could make flying more miserable: https://t.co/coXWQ7PInF — ProPublica (@ProPublica) April 3, 2017