Ukraine's parliament on Thursday voted to back attempts by the crisis-torn ex-Soviet nation to seek NATO membership, a move set to heighten tensions with Russia.
Ukrainian lawmakers by a vote of 276 to 25 approved legal amendments enshrining seeking membership in NATO as one of Kiev's foreign policy priorities.
"The time has come for us to clearly declare Ukraine's desire to join NATO in Ukrainian legislation," speaker Andriy Parubiy, who authored the draft bill, told parliament before the vote.
Ukraine has been fighting a Russian-backed insurgency in its eastern regions for more that three years and sees NATO accession as a key way of bolstering its defences against former master Moscow.
Ukraine's pro-Western leadership pledged to push to join NATO after ties with Russia collapsed over its seizure of the Crimean region, but Kiev is yet to officially apply to start the lengthy process of joining the US-led military alliance.
Russia rejects the accusations that it has been arming the rebels in Ukraine and sending its own troops across the border.
The Kremlin has long been angered by NATO expansion into what Moscow views as its sphere of influence in the former Soviet region and lashed out at the Ukraine vote.
"Moscow traditionally treats the process of NATO expansion towards our borders with distrust and concern," Kremlin spokesman Dmitry Peskov told journalists.
"We believe that this threatens our security and the balance of power in the Eurasian region."
This week the Balkan country Montenegro became NATO's 29th member despite the bitter Russian opposition to the move.