Ukrainian MPs have granted self-rule to parts of two eastern regions, and an amnesty to pro-Russian rebels there.
The law affecting Donetsk and Luhansk regions - which is in line with the 5 September ceasefire - was condemned by some MPs as "capitulation".
Meanwhile, Russia said it needed to boost troops in Crimea - Ukraine's peninsula annexed by Moscow in March.
The rebels in the east have been battling Ukrainian troops since their seizure of a number of towns in April.
Ukraine and the West have accused Russia of backing the separatists with soldiers and heavy weapons. The Kremlin denies doing so.
At least 3,000 people have been killed in the conflict and more than 310,000 internally displaced in Ukraine, the UN says.