The Federal Security Service (FSB) has detained a radical who fought against the Russian military and the DPR militia in Mariupol, according to an official statement.
"The Department of the Russian Federal Security Service for the Republic of Crimea and the city of Sevastopol… detained a member of a Ukrainian illegal armed group operating on the territory of a foreign state for purposes contrary to the interests of the Russian Federation", the statement says.
An investigation into the man is underway, as he may face up to 15 years in prison.
Russian forces and the DPR militia continue to advance in Mariupol, as they have recently seized the port, while the fighting is yet to cease in the city's industrial zone. The encirclement is tightening around the radicals, as Ukrainian forces have already failed to help them leave the city.
At the same time, over 1,100 Ukrainian troops have surrendered to the Donbass militia, the Russian MoD confirmed.