A combination of file photos show Russian President Vladimir Putin (L) and Ukrainian President Petro Poroshenko. (Xinhua)

MOSCOW, Dec. 10 (Xinhua) -- Ukraine's decision not to extend the friendship treaty with Russia is regrettable and against the Ukrainian people's interests, the Kremlin said Monday.

"We can only express regret for the fact that the Ukrainian leadership is making such hasty decisions that, from our viewpoint, are a manifestation of disrespect for their own people and their interests," Kremlin spokesman Dmitry Peskov told reporters.

Earlier in the day, Ukrainian President Petro Poroshenko signed a law to terminate the Treaty of Friendship, Cooperation and Partnership between Ukraine and Russia signed in 1997.

Tensions have flared up recently in the Kerch Strait after Russia seized three Ukrainian naval ships which allegedly breached the Russian border, while Kiev denied Moscow's "provocation" allegations.

Relations between Kiev and Moscow have been deteriorating since early 2014 over Crimea and eastern Ukraine.