Russian authorities have asked their Supreme Court to declare Ukraine's Azov Regiment a terrorist organization.

According to the Russian news agency Interfax, the Ministry of Justice in Moscow said that the court case "for declaring the Ukrainian paramilitary nationalist group" Azov "(other names used: Azov Battalion, Azov Regiment) as a terrorist organization and banning its activities on "The territory of the Russian Federation is scheduled for May 26."

This comes at a time when Ukrainian fighters, many of whom are members of the Azov Regiment, are being evacuated from the Azovstal steel plant.

A Kremlin spokesman Dmitry Peskov has previously declined to comment on whether the steelworks' defenders - who are now in Russian custody - will be treated as prisoners of war or war criminals.

The Azov Regiment was formed in 2014, shortly after Moscow annexed the southern Ukrainian peninsula of Crimea to fight Russian forces and pro-Russian rebels in the eastern Donbas region.

Some Azov fighters had links to nationalist and far-right groups. The regiment later joined the National Guard of Ukraine.