The United Kingdom’s Foreign Office signaled Thursday that it believes Russia is using the Wagner Group, a shadowy Kremlin-linked mercenary organization, to hunt down and kill Ukrainian President Volodymyr Zelenskyy.

Since the start of the war, Zelenskyy has said he is Russia’s “No. 1 target,” and U.S. officials have voiced repeated concerns about his safety. But the Ukrainian leader has refused to flee his country, choosing instead to stay in Kyiv, the capital, as it continues to ward off a Russian takeover.

The alleged founder and leader of the Wagner Group, Dmitry Utkin, is believed to have Nazi sympathies ― an irony if true considering how Russian President Vladimir Putin has justified his aggression in Ukraine by claiming it needs to be “de-Nazified.”

British Foreign Secretary, Liz Truss announced that the Wagner Group numbered among dozens of individuals and businesses to be newly sanctioned, describing it as “the organisation of Russian mercenaries reportedly tasked with assassinating President Zelenskyy.”

Also facing sanctions are Alfa Bank, five other financial institutions and a variety of individuals, including Russian Foreign Minister Sergei Lavrov’s stepdaughter, who reportedly lives in a multimillion-dollar London flat.

The European Union slapped sanctions on the Wagner Group and other entities accused of funding it back in December, citing serious human rights abuses by members.

Russia says it does not use the mercenary group, which it refers to simply as a private company. According to the Center for Strategic and International Studies, a Washington-based think tank, that plausible deniability comes in handy: “The Russian government has found Wagner and other private military companies to be useful as a way to extend its influence overseas without the visibility and intrusiveness of state military forces.”

European security officials suggested in February that hundreds of Wagner Group fighters had been trickling into eastern Ukraine to lay the groundwork for the war, according to The New York Times.

Ukraine’s defense ministry said on Sunday that a new group of Wagner mercenaries had entered the country with the aim of targeting the president and other high-ranking Ukrainian officials.

The group’s members have experience fighting in countries including Syria and Libya, where they have been linked to war crimes.