Facebook just censored the prime minister of Norway.

The social network is caught in a rapidly escalating spat over censorship, freedom of expression, and editorial responsibilities. At the centre of it is a Pulitzer Prize-winning photo taken during the Vietnam War of children fleeing in terror from a napalm strike — including 9-year-old Kim Phuc, who is naked.

Facebook's "community standards" prohibit nudity.

The front page of Aftenposten on Friday. Aftenposten Facebook recently deleted a post from a Norwegian author who shared the photo (and suspended him) — prompting Norway's biggest newspaper to write a scathing open letter to CEO Mark Zuckerberg, accusing him of "abusing" his power and abdicating his editorial responsibilities.

"Listen, Mark, this is serious," newspaper editor Espen Egil Hansen wrote in the open letter. "First you create rules that don’t distinguish between child pornography and famous war photographs. Then you practice these rules without allowing space for good judgment. Finally you even censor criticism against and a discussion about the decision — and you punish the person who dares to voice criticism."

Norwegian Prime Minister Erna Solberg waded into the row, posting the photo to Facebook, as did multiple other government ministers, Aftenposten reports.

"I appreciate the work of Facebook and other media to stop pictures and content showing abuse and violence," the PM wrote in an accompanying message. "But Facebook gets it wrong when it censors pictures like these. It contributes to restricting the freedom of speech."

But it seems Facebook doesn't care what Solberg thinks: It has now deleted her post, along with the ones posted by ministers.

"It is very regrettable that Facebook removed a post from my Facebook page," the Norwegian prime minister told Aftenposten.

Erna Solberg, prime minister of Norway. Sean Gallup / Getty A Facebook spokesperson provided Business Insider with the following statement:

"While we recognize that this photo is iconic, it’s difficult to create a distinction between allowing a photograph of a nude child in one instance and not others. We try to find the right balance between enabling people to express themselves while maintaining a safe and respectful experience for our global community. Our solutions won’t always be perfect, but we will continue to try to improve our policies and the ways in which we apply them."

It's worth noting that Facebook does have a "graphic content" warning it can place over potentially offensive photos or videos. It's not clear why it wasn't used in this instance.

"You are restricting my room for exercising my editorial responsibility. This is what you and your subordinates are doing in this case," Aftenposten editor Epsin Egil Hansen wrote to Zuckerberg. "I think you are abusing your power, and I find it hard to believe that you have thought it through thoroughly."