Russia plans to reinforce its Black Sea Fleet based in Crimea, which it annexed from Ukraine in March, Defence Minister Sergei Shoigu said on Tuesday.

"This year, the Black Sea fleet will receive (new) submarines and new-generation ships," Shoigu said in televised comments, without giving details of numbers.

New air defence units will also be opened at the fleet's bases, the minister said.

Russia's only warm-water fleet, providing it with access to the Mediterranean, and to the Atlantic and Indian Oceans beyond, is based at the Crimean port of Sevastopol.

Russia seized the port along with the rest of the peninsula in response to the fall in Kiev of a pro-Kremlin regime.

Shoigu said Russia has allocated a total of 86.7 billion rubles ($2.4 billion, 1.8 billion euros) to modernise the fleet up to 2020.

Russian media has reported that President Vladimir Putin will attend celebrations marking the anniversary of victory in World War II in Sevastopol on May 9, although this has not been confirmed by the Kremlin.

The Sevastopol celebrations will include a flypast of 70 planes, symbolising 70 years since Sevastopol was liberated from Nazi occupiers, Shoigu said.