"Russia operates in Ukraine, without consulting with the Ukrainian government, and thus strongly supports the separatists," Seibert said.
The Kremlin has repeatedly denied helping the so-called "DPR" and "LPR". But the statement of one of the militants Igor Martynov to German Frankfurter Allgemeine Zeitung that Moscow provides funds to self-proclaimed republics, suggests otherwise.
"Without the military and financial support from Russia there would not be violent separatism, which is now terrorizing these regions," Seibert said.
Russia has repeatedly denied that it actively supports the self-proclaimed republics, providing them with military and financial support while NATO and the EU stated they have evidence of Russian military presence.