The Russian Navy commander said on Friday that the Black Sea Fleet could increase the number of warships at the base in Sevastopol, in Ukraine's Crimea, to 100.
"The base agreement allows us to have up to 100 warships in the Black Sea Fleet, compared to the current figure of only 35; we may also have up to 25,000 personnel, while currently we only have 11,000," Adm. Vladimir Vysotsky said.
The commander said Russia needs the Black Sea Fleet to protect its national interests.
However, the Ukrainian ministry said: "The base agreement does not permit the Russian Black Sea Fleet to bring any new warships or [support] vessels to Ukraine."
Ships can only be replaced with the same class and type of vessel, the statement said.
The ministry stressed that increasing Russian Black Sea Fleet personnel "does not conform to the logic of its subsequent withdrawal from Ukraine."
Adm. Vysotsky had said Russia does not intend to withdraw its fleet from Sevastopol before the base agreement expires in 2017.
The Black Sea Fleet currently uses a range of naval facilities on the Crimean peninsula under an agreement signed in 1997. Ukrainian President Viktor Yushchenko recently ruled not to extend the lease for Russia's Black Sea Fleet beyond May 28, 2017.
Frequent disputes have flared up between Russia and Ukraine over the lease of the naval facilities on the Crimean peninsula. In the latest row, Moscow Mayor Yury Luzhkov was barred from entering the former Soviet republic over a speech in which he questioned Ukraine's right to sovereignty over the region.
