(Reuters) – Ukraine accused Russia on Friday of illegally pressuring Ukrainians in occupied territory to change their legal status or leave, and said it would report the practice to the International Criminal Court.

Russia – which controls nearly a fifth of Ukraine’s territory – issued a presidential decree on Thursday saying Ukrainian citizens living “in Russia without legal grounds” should “regulate” their status by September 10.

It did not spell out what it meant by regulate, though Russia has been pressing Ukrainians in those areas to obtain Russian citizenship.

Heorhii Tykhyi, Ukraine’s foreign ministry spokesman, said the move was a “despicable act”.

“It is yet another step in Russia’s campaign of discrimination, persecution and forced displacement of Ukrainian citizens from their homeland, or forcing them to acquire foreigner status,” he told a briefing in Kyiv.

Russia, which regularly denied accusations of carrying out abuses, did not immediately respond to a request for comment sent to its foreign ministry.

President Vladimir Putin’s decree affects Ukrainians who live in the Crimean peninsula – annexed by Russia in 2014 – as well as occupied parts of Donetsk, Luhansk, Zaporizhzhia and Kherson regions.

Moscow unilaterally declared the Ukrainian regions to be Russian territory in 2022 after launching its full-scale invasion.

“Ukraine … appeals to the International Criminal Court with a requirement to take into account this decree as additional evidence of war crimes by the leadership of the Russian Federation,” Tykhyi said.

In March 2023, the ICC issued arrest warrants for Putin and his children’s commissioner, Maria Lvova-Belova, accusing them of illegally deporting children from Ukraine.

Kyiv says it has officially confirmed the illegal abduction of at least 19,000 children by Russia since Moscow launched the full-scale war. Russia says it was helping the children to leave the war zone.

(Reporting by Yuliia Dysa; Editing by Andrew Heavens)