After being detained in camps operated by Russian intelligence officials, many Ukrainians are then forcibly relocated to economically depressed areas in Russia, in some cases thousands of miles from their homes, and often left with no means of returning, sources said.

Although some Ukrainians have voluntarily entered filtration camps to try to escape the fighting by entering Russia, many have been picked up against their will at check points and in bomb shelters. After spending an average of around three weeks at the camps — where sources and eyewitnesses say they are held in inhuman conditions, interrogated and sometimes tortured — some are sent across the border into Russia and given state documentation.

From checkpoints in Rostov and other Russian towns, many Ukrainians are then relocated to far-flung corners across Russia, the sources said. In some cases, Ukrainians have been sent to Sakhalin Island, a distant spit in the Pacific Ocean on Russia’s far east — 10,000 miles from the Ukrainian border. If they are fortunate, sources tell CNN, Russia will provide housing in residential areas and perhaps a Russian SIM card and a small amount of money.