A U.S. taxpayer-funded broadcaster this fall published a ­Spanish-language opinion piece warning that the “Islamization” of Europe by migrants is destroying the continent’s Christian character and posing a danger to the United States “greater than that from the Nazis in the 1940s.”

The online piece followed stories by the same government-run publisher, Radio and Television Martí, that described philanthropist and prominent Democratic donor George Soros as a “nonpracticing Jew of flexible morals” and as a “left-wing billionaire of Hungarian-Jewish origin.”

The federal agency that oversees Martí launched an internal investigation this fall after a May report about Soros was publicized and widely denounced. The probe has now expanded to include examining how Martí came to publish an earlier story that included anti-Semitic language about Soros, a U.S. citizen, as well as the anti-Muslim piece, the agency confirmed.

Four Martí employees have been placed on leave and two contract staffers have been fired, according to Nasserie Carew, a spokeswoman for the U.S. Agency for Global Media. All are reporters and editors, according to biographies on Martí’s website and on social media.

Anchor Maite Luna, who said she was one of the fired contract staffers, told The Washington Post that she was only doing what she had been instructed to do by editors when she promoted May’s Soros report on her morning news program. Luna declined to say more, citing the advice of attorneys.

The five other employees or contractors either declined to comment or could not be reached.

For nearly three decades, Martí has broadcast news and other programs promoting U.S. interests to audiences in communist Cuba, seeking to circumvent state-controlled media. Martí spent nearly $29 million in 2017 on its mission to provide “accurate, balanced and complete information” to the island’s residents.

Since June, the Office of Cuba Broadcasting, which operates Martí, has been run by Tomás P. Regalado, a former mayor of Miami. Martí referred questions to the U.S. Agency for Global Media, or USAGM, which also oversees the more widely known Voice of America.

In a statement Wednesday, ­USAGM said it is conducting a “full content audit” of Martí’s work to identify any unprofessional reporting. The agency also said it had provided “ethics and best practices training” for the staff of Martí and is hiring a “standards and practices” editor.

Carew confirmed that the three pieces deemed offensive had been removed from Martí’s website, which is accessible to
a Spanish-language audience around the world. May’s Soros story was publicized by a blogger in October, and the other Soros story was described in a report last month by El Nuevo Herald, a Spanish-language publication in Miami.

The Post recovered Martí’s ­anti-Muslim opinion essay, published in September, from Google’s cache. It features a large image of Muslims kneeling in prayer in a street in Paris over the headline: “Europa + Arabia = Eurabia.”

The article was written by Juan Felipe Benemelis, a Cuban-born author who has described
himself as the “Spanish-language Kissinger” and has said he is “considered the foremost expert in Islamic culture, Africa, international politics and terrorism.”

Benemelis did not respond to phone calls, emails or messages sent to a Facebook account where he posts often.

His nearly 1,500-word essay decries the “Islamization that is happening in European cities,” describing it as the result not of desperate migration from war-torn countries but of a decades-old “deliberate strategy of Muslim leaders” to weaken opposition to sharia law and ultimately take over the continent.

Benemelis portrays Islam as inherently violent and writes that Europeans must turn back Muslim migrants to save Western democracy and culture.

“Christianity in Europe is in retreat, on the defensive, while Islam is on the offensive. . . . The West must stop the migrations and deconstruct the black history of its civilization that has been transmitted to us,” Benemelis wrote.

Benemelis had never written for Martí before May, when he wrote three opinion pieces in nine days, including one suggesting that President Trump was improving conditions in the Middle East by taking a hard line against Iran.

Carew said Benemelis was never paid for the four opinion pieces he wrote for Martí, and she declined to say whether Benemelis had any agreement with Martí that was terminated.

The Post was also able to locate versions of Martí’s broadcasts about Soros still circulating on Facebook, Twitter and other social media sites.

The 88-year-old businessman and naturalized U.S. citizen has been a top donor to Democratic candidates in recent years. He has also become a focus of conspiracy theories, often cast as a puppet master behind forces impeding Trump.

Commentators on Fox News have repeatedly asserted, without evidence, that Soros funded the advance of a migrant caravan that was approaching the U.S.-Mexico border. In October, Trump cited professionally printed signs held by protesters heckling the confirmation of Supreme Court Justice Brett M. Kavanaugh to suggest Soros must be behind the effort.

“The very rude elevator screamers are paid professionals only looking to make Senators look bad,” Trump tweeted. “Don’t fall for it! Also, look at all of the professionally made identical signs. Paid for by Soros and others. These are not signs made in the basement from love!”

Three weeks later, a pipe bomb was discovered in Soros’s mail amid a series of similar mailings to prominent Democrats, allegedly sent by a Florida man, a fervent Trump supporter. Soros was unharmed.

Two days after that, on Oct. 26, a U.S. researcher blogged about a nearly 15-minute “Special Report” on Soros that he spotted on Martí. The May report made sweeping and unfounded claims, including that Soros was secretly funding violent leftist uprisings to topple governments from Romania to Colombia. The report also falsely described Soros as “the architect of the financial collapse of 2008.”

The video report, which aired in several installments, credited the U.S. conservative group Judicial Watch with “keeping an eye” on Soros.

The report accused Soros of financially supporting a violent rebel group turned political party known as the Revolutionary Armed Forces of Colombia, or FARC — something Judicial Watch has asserted in writings before and after the Martí report. Laura Silber, a spokeswoman for Soros’s Open Society Foundations, said the Soros organization’s efforts in Colombia supported programs that embody “the essence of American ideals,” such as fighting corruption and promoting the rule of law.

In letters last month apologizing to Soros and his organization, USAGM chief executive John F. Lansing, a former head of Scripps Networks, faulted the report’s “weak sourcing” and suggested that Judicial Watch may have been the only source.

“I deeply regret that a USAGM network produced something that feeds into age-old tropes against the Jewish community, at a moment when anti-Semitism is growing at home and around the world,” Lansing wrote.

Judicial Watch also appears to have served as the foundation for the earlier Martí report on Soros, which was unknown to Soros’s organization until The Post shared a link to the story last week. The existence of the Martí article was first reported in El Nuevo Herald, a sister publication of the Miami Herald.

The Martí report, published on April 1, was written by Armando de Armas, who has written hundreds of articles for Martí over the past decade. De Armas did not respond to phone messages or one left on Facebook.

The article reported that a lawsuit filed by the “prestigious Judicial Watch” was seeking documents that might show whether the State Department had subsidized Soros’s political activities. It also noted that Soros is of “Hungarian-Jewish origin.”

Carew declined to say whether de Armas had been placed on leave or faced disciplinary action. He is not among the four federal workers named as being on administrative leave in connection with the investigation.

In an interview, Tom Fitton, the president of Judicial Watch, said Martí and his organization were never in contact before the reports aired. Fitton declined to comment on whether he considers the Martí reports to be anti-Semitic.

“I don’t speak Spanish. . . . I didn’t see the broadcast and I don’t know how it translated,” he said.

In a statement, Silber, the spokeswoman for Soros’s organization, said that the apology ­USAGM offered for the one, previously known broadcast is no longer sufficient.

“We appreciated that the initial apology made by the U.S. Agency for Global Media for its taxpayer funded anti-Semitic programming about George Soros, but it is now clear this was not a one-off incident,” Silber said. “We are deeply concerned to learn about additional content with the same nefarious, anti-Semitic undertones. USAGM needs to be much more forthcoming and Congress needs to conduct more vigorous oversight. In the end we want to know how this content got made, who made it, and who’s been held accountable so that it will not happen again.”

Julie Tate contributed to this report.