Both Moscow and Kyiv have escalated attacks on the key waterway since Russia in July exited a deal guaranteeing safe passage for cargo ships to and from Ukraine's Black Sea ports.

"We have signed an agreement, and in the near future there will be a permanent point of deployment for the Russian navy in the Ochamchire district," the leader of separatist Abkhazia, Aslan Bzhania, told the Russian tabloid Izvestia.

Bzhania, who was scheduled to have met with Russian President Vladimir Putin this week, said the purpose of the deal was to "increase the defence capability both of Russia and Abkhazia," according to the interview published Thursday.

"And this kind of cooperation will continue, because this safeguards the fundamental interests of both Abkhazia and Russia. And security is above all," he added.

Russia has permanent military bases stationed in Abkhazia and another Moscow-backed separatist region, South Ossetia, both of which it recognised as independent states in the wake of its war with the Caucasus country in 2008.

Ukraine last month struck the headquarters of Russia's Black Sea fleet on the annexed Crimean peninsula, marking a major blow for Moscow.