Russian President Vladimir Putin said Monday that Moscow was considering recognizing the independence of east Ukraine's two separatist republics, a step that would further escalate the Ukraine crisis.
The rebel leaders of Donetsk and Lugansk made a coordinated appeal to Putin for Moscow to recognize them earlier on Monday.
The Russian parliament has also asked Putin to recognize the pro-Moscow separatist territories, which declared themselves independent of Kyiv's rule after Ukraine's 2014 pro-EU revolution.
"Our goal is to listen to our colleagues and determine our next steps in this direction, bearing in mind both the appeals of the leaders of the DNR and LNR to recognize their independence," Putin said, using the acronyms for the two separatist regions.
Putin made his remarks during an unscheduled meeting of Russia's Security Council, which brings together the country's most senior defense and security officials.
Calls for recognition from the rebels came as the Ukraine crisis escalated sharply on Monday, with fears mounting that Russia is paving the way for an all-out invasion of its western neighbor.
"I ask you to recognize the sovereignty and independence of the Lugansk People's Republic," separatist Leonid Pasechnik said in a video aired on Russian state television.
Denis Pushilin, the rebel head of the Donetsk People's Republic, made a similar appeal.
"On behalf of all the people of the Donetsk People's Republic, we ask you to recognize the Donetsk People's Republic as an independent, democratic legal and social state," Pushilin said.
He said the move could possibly "prevent casualties among civilians," accusing Ukraine of planning an attack, which Kyiv has firmly denied.
Pushilin also asked Putin to agree on a "friendship" agreement with the breakaway territory, that would include cooperation in defense.
Washington has said that Moscow's recognition of the territories would "constitute a gross violation of international law."
The West accuses Russia of preparing to attack Ukraine after surrounding it with more than 150,000 troops.
Russia has denied planning an invasion.