Ukrainian President Volodymyr Zelensky on Monday angered Moscow by accusing it of "oppressing" Ukrainians living in parts of Russia "historically inhabited by Ukrainians".
Russia and Ukraine have for years fought a bitter cultural battle over the two countries' closely entwined histories -- one that has escalated dramatically since Russia invaded its western neighbour in February 2022.
Zelensky's office published a decree saying Russia has historically denigrated the rights of Ukrainians living in southern and western Russia and continues to do so.
The law -- entitled "on the territories of the Russian Federation historically inhabited by Ukrainians" -- named six modern-day regions of western and southern Russia that Zelensky said had been historically home to "ethnic Ukrainians."
They were: Belgorod, Bryansk, Krasnodar, Kursk, Rostov and Voronezh.
"For centuries Russia has systematically committed, and continues to commit, actions aimed at destroying national identity, oppressing Ukrainians (and) violating their rights and freedoms," the decree said.
It said that the ethnic Ukrainians should be allowed to be educated in the Ukrainian language, have access to Ukrainian media and enjoy freedom of assembly and religion.
Many Ukrainians have shunned the use of the Russian language, which was a native tongue for millions, and cities across the country have renamed streets and removed statues honouring Russian and Soviet figures.
Other Topics of Interest Putin's 143 Million Prisoners Russia is a criminal organization where elections are window-dressing and speech is about as free as it is inside China’s Politburo, Diane Francis writes.
Zelensky's remarks come as Moscow has said its invasion is driven by protecting ethnic Russians living in Ukraine.
President Vladimir Putin has repeatedly denied the existence of a Ukrainian nation.
His ally, former president Dmitry Medvedev, blasted Zelensky's decree as a "propaganda move."
"There is nothing to comment on because Ukrainians are Russians," Medvedev, who has emerged as one of the most hawkish figures in Russia during the invasion, said on Telegram.
He used an imperial-era phrase to describe the territory of modern-day Ukraine, saying: "Malorossiya (Little Russia) is part of Russia."
In a 5,000-word essay published months before the offensive entitled "on the historical unity of Russians and Ukrainians", Putin said there was no "historical basis" for "the idea of Ukrainian people as a nation separate from the Russians."
The article was criticised by independent scholars as a manipulation of history.