Russia's Foreign Minister Sergei Lavrov has warned that protests in Ukraine are "getting out of control".
He described violent clashes between anti-government protesters and police as "scary" and accused EU politicians of stirring up the situation.
There has been a second consecutive night of clashes in Kiev.
Young men threw fireworks and petrol bombs at police guarding the road leading up to the Ukrainian parliament. Police violently beat some protesters.
The violence—which has been restricted to a small area around Hrushevskyy Street—abated on Tuesday morning, but correspondents say there is a widespread expectation that it could resume later in the day.