Russian lawmakers on Tuesday called on President Vladimir Putin to recognize the two breakaway eastern Ukrainian regions of Luhansk and Donetsk as "people's republics."
If the resolution is approved by Putin, it would essentially give diplomatic recognition to the regions where Russian-backed separatists have been fighting with Ukrainian government forces since 2014.
Such a move would dramatically escalate tensions at a time when the world is on edge over fears Russia could invade its neighbour.
The State Duma, Russia's lower house, overwhelming voted on Tuesday to send the document to the president.
Duma leader Vyacheslav Volodin said the proposal would be on Putin's desk immediately.
A Kremlin spokesperson said that the State Duma reflects the will of the Russian people, but emphasized that Putin had yet to take a position on the issue.
The Russian rouble is already the common currency in Luhansk and Donetsk. Russia has given hundreds of thousands of people citizenship there and is heavily involved in area's social services and economy.
The Duma's request was met with enthusiasm by the separatists.
"This is a long-awaited decision by the citizens of the Donetsk People's Republic and Russia," said Vladimir Antonov, who describes himself as the region's deputy prime minister.
Kiev condemned the resolution
The government in Kiev, however, condemned the resolution.
Ukrainian Foreign Minister Dmytro Kuleba said Russian recognition of the separatist regions would be taken as evidence that Moscow has abandoned the Minsk peace agreements.
The Minsk plan was agreed under Franco-German mediation in 2015 and provides for the reintegration of the pro-Russian separatist areas into Ukraine with far-reaching autonomy.
It has never been fully implemented and the sides frequently disagree on its terms.
Despite ceasefire attempts, Western-equipped Ukrainian government forces have been fighting Russian-backed separatists in the regions near the Russian border since 2014.
According to UN estimates, more than 14,000 people have been killed since then, mostly in the separatist-held areas.