A branch of the Russian-owned news outlet Sputnik reported as real a fake story that Israel had used a nuclear weapon on Syria from YourNewsWire, a fake news site that experts have described as a Russian proxy and a pusher of Russian-supported narratives.

On April 30, Israel launched a missile attack on facilities in Syria allegedly connected to Iran and its proxies. YourNewsWire, a site known for its fake stories, published a piece baselessly claiming that Israel had used a “tactical nuclear bomb on Syria” in “the first nuclear bomb deployed in armed conflict since the US dropped atomic bombs on Hiroshima and Nagasaki in 1945,” according to unnamed “local reports.” The site, to back up its claim, linked to a Facebook video of an explosion that says nothing about nuclear weapons.

As fact-checking sites Lead Stories and Snopes noted, there is no proof that there was any nuclear attack. Not even Syria’s state-run news agency reported such a claim.

Nonetheless, on that same day, Sputnik Arabic published a piece with the headline (as translated by Google) “Israel bombed Syria with its first tactical nuclear bomb” that directly linked to YourNewsWire’s fake story. Sputnik also posted its story on its Facebook page, writing (based on Facebook’s translation) that there were “allegations” that Israel used a nuclear weapon on Syria. The fake story was also spread by an Iraqi province official and by an Al Jazeera host.

YourNewsWire, one of the most popular fake news sites on social media, often posts stories that fit Russia’s narratives. Sean Adl-Tabatabai, who runs the site, has said that he “love[s]” fellow Russian outlet RT and that it’s a favored source of his. In turn, an agency of the European Union that focuses on Russia misinformation has criticized the site for publishing fake stories that favor Russian policy, and a former U.S. intelligence official has called the site a Russian “proxy.”