US Ambassador to Germany Richard Grenell has come under fire for demanding an independent probe into Germany's most significant journalism scandal in decades, after Der Spiegel admitted on Wednesday that one of its star journalists, Klaas Relotius, had fabricated reports for years; much of it anti-American in nature.

Der Spiegel, Europe’s biggest-circulation current affairs magazine, revealed on Wednesday that award-winning writer Claas Relotius had been making up much of his reporting around the world, including crucial details in a colorful series of pieces about the U.S. that painted supporters of President Trump in Arizona and Minnesota as bigoted, radical, and at times xenophobic. -WSJ

In addition to having several awards stripped from him, the 33-year-old Relotius now faces embezzlement charges for allegedly soliciting donations for Syrian orphans from readers "with any proceeds going to his personal account," according to the BBC.

Claas Relotius

In a late Friday letter to Der Spiegel's editor in chief, Grenell requested an "independent and transparent investigation" to determine how the fraud went undetected for so long, adding that the revelations "are troubling to the US Embassy, particularly because several of these fake stories focused on US policies and certain segments of the American people."

US Ambassador to Germany, Richard Grenell

"We are concerned that the leadership of Der Spiegel encourages this form of reporting and that the reporters appear to deliver what the leadership wants," wrote Grenell, who accused the paper of anti-American bias, and said the German paper "routinely included information and stories which could have been proven untrue if they had checked the facts with the Embassy first."

"It is clear that we were the victims of a campaign of institutional bias," Grenell wrotem adding "...it is routine practice for Spiegel reporters to not even call us before writing."

Der Spiegel responded to Grenell, apologizing "to all American citizens who have been insulted and slandered by these reports," yet pushing back against Grenell's accusation of anti-American bias.

"If we criticize the American president, it is not anti-Americanism, but criticism of policies of the man in the White House," wrote Der Spiegel deputy editor in chief Dirk Kurbjuweit.

Grenell hit back - tweeting "@DerSPIEGEL says they don’t have any anti-American bias. But the facts tell a different story. Below are only a few examples."

. @DerSPIEGEL says they don’t have any anti-American bias. But the facts tell a different story. Below are only a few examples. @sefi99 #spiegelgate pic.twitter.com/zf5uraPoqD — Richard Grenell (@RichardGrenell) December 21, 2018

Grenell has been attacked for his letter to Der Spiegel. ZDF journalist Andreas Kynast tweeted "In the logic of an administration that sees any critical consideration as a country insult @DerSPIEGEL, this is, of course, anti-American. But also anti-German, anti-European and anti-earthly," to which Grenell shot back "We value policy criticism. We love a free press. But @Spiegel literally fabricated stories saying people (Americans) were racist & xenophobic. They made up events, details, & lies - and no editor checked the stories. Every real journalist should be outraged by this."

We value policy criticism. We love a free press. But @Spiegel literally fabricated stories saying people (Americans) were racist & xenophobic. They made up events, details, & lies - and no editor checked the stories. Every real journalist should be outraged by this. https://t.co/CVlSqgXIQe — Richard Grenell (@RichardGrenell) December 22, 2018

Brookings Institute senior fellow Constanze Stelzenmüller took a shot at Grenell's letter, which she said suggests journalists should "call US Embassy before they start writing."

Are you serious? Did you even read what Ambassador Grenell wrote? What you tweeted here is far from a misinterpretation of his letter. All stories should be sourced from both sides, which is standard journalistic practice. You must know this, ma'am. — Jennifer_Williams (@JenniferW1776) December 23, 2018

Nope. Not true. Be accurate. We simply suggest reporters who write about us actually call us for reaction. https://t.co/XacXiPUh4d — Richard Grenell (@RichardGrenell) December 22, 2018

The attacks on Grenell for demanding an investigation into a massive fraud on Der Spiegel's readership have not gone unnoticed.

.@RichardGrenell is being attacked by German media because he’s asking them not to fabricate stories, people, places, and times about how horrible and racist Americans are. — John Cardillo (@johncardillo) December 22, 2018