Ukraine's Prime Minister Arseniy Yatsenyuk accused Russia of trying to destroy Ukraine as an independent country and attempting to restore the USSR, reports Reuters. 

In Yatsenyuk's words, only NATO could defend Ukraine from external aggression. 

"We are still in a stage of war and the key aggressor is the Russian Federation ... Putin wants another frozen conflict (in eastern Ukraine)," Yatsenyuk told on Saturday a conference in Kiev, attended by European and Ukrainian lawmakers and business leaders.

Yatsenyuk said Putin would not be content only with Crimea - annexed by Moscow in March - and with Ukraine's mainly Russian-speaking eastern region.

"His goal is to take all of Ukraine ... Russia is a threat to the global order and to the security of the whole of Europe," said Yatsenyuk, who is known for his hawkish rhetoric.

Asked about future NATO membership, a red line for Russia, Yatsenyuk said he realised the alliance was not ready now to admit Kiev, but added: "NATO in these particular circumstances is the only vehicle to protect Ukraine."