ISTANBUL, Oct 1 (Reuters) - Turkey's Foreign Ministry said on Saturday it rejects Russia's annexation of four regions in Ukraine, adding the decision is a "grave violation" of international law.Ankara opposes Western sanctions on Russia and has close ties with both Moscow and Kyiv, its Black Sea neighbours.Register now for FREE unlimited access to Reuters.com"This decision, which constitutes a grave violation of the established principles of international law, cannot be accepted," the ministry said."We reiterate our support to the resolution of this war, the severity of which keeps growing, based on a just peace that will be reached through negotiations," it added.Ukrainian President Volodymr Zelenskiy said on Friday his country had submitted a fast-track application to join the NATO military alliance and that he would not hold peace talks with Russia while Putin was still president."