President Vladimir Putin has issued a decree that Russia is temporarily accepting passports and other identity documents issued by the self-proclaimed rebel republics in eastern Ukraine, the media reported on Sunday.
The decree covers the self-declared Donetsk People's Republic and Luhansk People's Republic, the BBC reported.
"Identity papers, school or professional diplomas, birth and death certificates... issued by the competent bodies in the zones mentioned are recognised as valid by Russia," it said.
Russia's Foreign Minister Sergei Lavrov said the move it was a "humanitarian decision".
Lavrov, who is currently in Munich for a NATO conference, also announced that heavy military hardware would be withdrawn from the region, and said a ceasefire would come into force on Monday.
Ukrainian President Petro Poroshenko has condemned the decision to recognise separatist passports.
Government officials in Ukraine called the decision a "deliberate escalation".
Foreign minister Pavlo Klimkin said: "This decree fundamentally contravenes the logic of the Minsk agreements (2015 ceasefire deal signed in Minsk)."
Former acting President Oleksandr Turchynov, now the head of Ukraine's national security and defence council, echoed this, saying the Kremlin had "completely ruled out" a return to the ceasefire agreement, the BBC said.
Turchynov said: "The Minsk process provides for the de-occupation of eastern Ukraine and its restitution to the legal force of the state.
More than 9,700 people have died since the Ukraine conflict erupted in 2014 after Russia annexed Ukraine's southern Crimea peninsula.
Pro-Russian rebels later launched an insurgency in the east.
A ceasefire was agreed in February 2015 but there have been frequent violations. The latest truce began on December 23.