Ukraine’s security service on Thursday revealed the names of four Russian generals whom it says were fighting with so-called separatists in Ukraine, a statement from the secretary of Ukraine's National Security and Defense Council said. The statement said Ukrainian forces were facing “structured military units of Russian regular army” troops organized along the same formations as the Nazis' Waffen SS units, a reference to German troops in World War II.

In the statement, Secretary Oleksandr Turchynov identified the four Russian generals as Andrey Serdyukov, who fights under the code name Sedov; Alexey Zavizyon (aka Pilevin); Evgeniy Nikiforov (aka Morgun); and Sergey Yudin, who was recently rotated out.

Russian officers hold key positions with the so-called separatists, while residents of the Donbass region of eastern Ukraine make up 40 percent of the forces, in addition to mercenaries and contract soldiers from Russia, the statement said. The troops have been organized into two army corps, one in the Donetsk region and the other in Luhansk. The mix of professional soldiers and volunteers mimics the structure of the Nazi Waffen SS unit, which also used volunteers, the Ukrainian government statement said.

A tweet sent by the presidential administration detailed that Russian military leaders were purportedly managing militants.

In July, Ukraine released the names of other generals believed to be involved in the conflict, RFE/RL reported.

Nazi comparisons and terminology have been cited by both sides, with Russia describing the Ukrainian government in Kiev as fascist and run by Nazis. Russia continues to deny any direct involvement in the conflict in Ukraine, saying that any Russian citizens fighting there are doing so as volunteers, not officially part of the Russian military.

Earlier this week it was reported that a Russian website accidentally published and then quickly removed the number of soldiers killed and wounded in Ukraine, along with the amounts of financial compensation they receive.

More than 6,700 people have died and at least 1.4 million have been displaced as fighting continues in the Donbass region. The Ukrainian government will have to continue with a seventh wave of mandatory conscription after failing to meet its goal of 25,000 conscripts, as reported last week.