The far right complains after the search engine DuckDuckGo vows to limit Russian propaganda.

DuckDuckGo has little control over its search results because they are provided by Microsoft’s Bing, which announced that it would follow the European Union’s order to restrict access to the Russian state news agencies RT and Sputnik.

But the criticism from the far right was directed at DuckDuckGo. The conservative website Breitbart said DuckDuckGo was “adopting the censorship policies” of Big Tech. In social media channels devoted to conspiracy theories, users vowed to switch to alternatives like the Russian search engine Yandex. The hashtag #DuckDuckGone trended across Twitter in the United States by Friday. And on YouTube, users criticized the company for silencing voices.

“If you’re using DuckDuckGo, I suggest you stop using it and switch to something else,” said Tarl Warwick, a self-described libertarian YouTube user with nearly half a million followers. He added: “I want tens of thousands of people to stop using it.”

In a statement, Kamyl Bazbaz, the vice president of communications for DuckDuckGo, said that the affected sites were engaged in “active disinformation campaigns,” meaning they were similar to other low-quality websites already penalized by search algorithms.

“This isn’t censorship, it’s just search rankings,” he said.

The backlash underscored the difficulties some technology companies face in limiting the spread of Russian propaganda at a time when pockets of America express support for the Kremlin and believe Big Tech companies are censoring their views.