Ukrainian officials declared on Sunday that a pro-government volunteer battalion had captured two wounded Russian soldiers in the country's restive eastern Donbas region. Authorities interrogated the two men and have moved them to a hospital in Kiev.

Footage of some questioning was uploaded to YouTube and later posted to Facebook by Ukrainian MP Anton Gerashchenko. In the video, a purported sergeant of the elite Third Brigade of the Russian special forces gives his name as Alexandrov Alexander Anatolievich and says that he is a "military servant of the Russian Federation."

The captured fighter lies under an emergency thermal blanket throughout the nearly 9-minute video as he relays details to his captors about the 14-member unit that he had been fighting with in Ukraine's Luhansk region since May 6, according to subtitles provided by the Ukrainian government. He appears to name some of his fellow soldiers and says that he was injured after being noticed while conducting a surveillance operation in the southern part of Shchastya city. He goes on to suggest that there are seven to eight groups of contracted Russian soldiers working in the Luhansk region.

The subtitles at the beginning of the video name the second prisoner of war as the unit's captain, Yerofeyev Yevgeniy Vladimirovich.

VICE News has not been able to independently verify the authenticity of the video. When reports asked Kremlin spokesperson Dmitry Peskov to comment on the footage and the Ukrainian governments announcements, he said, "Both we and the defense ministry have repeatedly said that there are no Russian servicemen in Donbas."

Though Russian soliders are widely believed to be operating in eastern Ukraine, Russia has continually denied that it has sent soldiers or arms to assist pro-separatist forces. The country's government has so far conceded only that Russian volunteers might be operating in the region.

Meanwhile, a commander with the Luhansk People's Republic militia acknowledged the troops' capture and appeared to dispute their identification as Russian special forces, identifying them instead as Luhansk servicemen who had volunteered some months ago. He said that he has documentation that supports this.

Ukrainian authorities said that they would allow Ukrainian journalists to interview the detainees later on Monday. The chief of Ukraine's Security Service suggested the men would not be used in any hostage exchange with Russia, and would instead be "facing criminal responsibility," according to Interfax News Agency.

A pro-Ukrainian forces medic, Grigory Maksimets, told the Associated Press that he treated the wounded soldiers when they arrived at his intensive care unit at the hospital in Shchastya after their capture late Saturday. One man had apparently sustained a shoulder injury while the other had been wounded in the right leg, the medic said.

"They asked not to be sedated because they were afraid we would take their organs," he added.

Kiev and the West maintain that Moscow has sent thousands of troops to assist with the separatist uprising in Ukraine's Luhansk and Donetsk regions. A recently released 64-page report detailing Kremlin involvement in the conflict, undertaken by the assassinated Russian opposition leader Boris Nemtsov before he was gunned down near the Kremlin in February, has countered the government's denials.

The report, completed and released by Nemtsov's allies last week, alleged that at least 220 Russian soldiers died in two key battles in Ukrainian cities of Ilovaisk and Debaltseve.

More than 6,100 people have been killed since the conflict began.