KIEV, Ukraine — Ukraine's armed forces have said that a Russian news story claiming that a British terrorism suspect — the so-called White Widow — was killed fighting pro-Russian separatists in Ukraine is an obvious fake. The story, which emerged from a Russian news agency, made the the front page of the Daily Mirror and was prominently reprinted in the Evening Standard and the Daily Mail.

The British newspapers ran the story on Wednesday based on an unsourced report by Russia's Regnum news agency that a Russian volunteer sniper killed Samantha Lewthwaite, a militant Islamist, about two weeks ago near the eastern town of Debaltsevo, one of the flashpoints in the Ukrainian conflict's fast-collapsing ceasefire. Regnum claimed that Lewthwaite, the former wife of a suicide bomber in the 2005 London attacks, had joined the pro-Kiev Aidar volunteer battalion as a sniper herself after entering Ukraine from Somalia.

Aidar commander Serhiy Melnychuk told BuzzFeed News, however, that the report was false. "We don't have any White Widows, and nor could we," he said. "[The Russians are] trying to drive a wedge between us and our British allies." Melnichuk and deputy commander Serhiy Grab said the battalion is actually based near the rebel stronghold of Luhansk — about 125 miles east of Debaltsevo.

"There's more chance of confirming that Bin Laden was fighting there," Roman Vybranovsky, a spokesman for Ukraine's national security council, told BuzzFeed News. "An Islamic terrorist fighting for a Ukrainian volunteer battalion while there are Chechen mercenaries on the [rebel] side is a more-than-eccentric idea," he said.

Alexei Toporov, the author of the piece and a former rebel press officer, insisted that he had checked the information with anonymous sources and vouched for its authenticity. "I talked to the people who shot her. They prefer to remain incognito," he told BuzzFeed News. "I have no reason not to trust them — I know that the information is 100% correct."

As proof, Toporov provided what he said was a scan of a fake South African passport that Lewthwaite, 30, supposedly used to enter Ukraine, which the Russian sniper allegedly found on her after he shot her. The photograph exactly matches a file photo of the fake South African passport that authorities in Nairobi say Lewthwaite used to enter Kenya in 2011 — including the angle from which it was taken and the light reflecting onto the passport.

Lewthwaite is rumored to have ties to the Somali radical Islamist group Al-Shabaab and has been linked — albeit not definitively — to several attacks in Kenya, where she is wanted on charges of planning bomb attacks. Another British tabloid, the Daily Star, claimed in September that she was training suicide bombers for ISIS in Syria.

"We are aware of reports," a spokesperson for Britain's Foreign Office told BuzzFeed News.

The Lewthwaite story appears to be the latest manifestation of a common myth among the Russian-backed rebels that Ukraine has hired foreign mercenaries to fight them, including female snipers. LifeNews, a pro-Kremlin channel with barely concealed links to the Russian secret services, reported in May that rebels had come under fire from female snipers in their strongholds of Donetsk and Luhansk.

The female sniper myth has its roots in the story of the "White Stockings," an Amazon-like mercenary battalion from the Baltics who Russian officials said fought against them in the first Chechen war and the 2008 Russo-Georgian war. Pro-Russian news outlets have similarly claimed Ukraine has deployed hired guns from Poland, the murky American private security company Greystone, and "mercenaries of the negroid race." None of the stories have been independently confirmed.

Unlike Russia's more reputable news wires — the government-controlled TASS and RIA Novosti and the privately held Interfax — it is rare to see a story from the far murkier Regnum cited so widely in the Western press. Estonia's secret services claimed in 2005 that Regnum "is not an ordinary information agency, but a structure controlled by the power elite and special services of Russia via which they try to affect [the] internal political situation in the neighboring countries in the direction favorable for Russia." Its founder, former Kremlin adviser Modest Kolerov, has been declared persona non grata in Estonia, Latvia, Lithuania, and Georgia, according to RIA Novosti.