Letter to Jews in Ukraine fake but anti-Semitism is not

In Donetsk, Ukraine, masked men reportedly handed out a letter requiring Jews to register with the government, report all their property or they would lose their citizenship and be deported. Thankfully, by all accounts, the letter is a fake.
The fact that there is no official movement by the government to persecute the Jews in the Ukraine is a relief, however the anti-Semitism and urge to resort to the old familiar scapegoating does exist and is worrisome.

Who actually came up with this plan to harass the Jews of Donetsk?