The French anti-submarine frigate Dupleix is to join on Monday the country's vessels in the Black Sea.

Its mission is scheduled to continue from April 14 to May 1, according to the website Infosdefense.com, cited by UNIAN news agency.

Dupleix is among older frigates of the French Navy. It is also equipped with Exocet and Crotale missiles, whith enables it to defend strategic positions.

It is the third French military vessel to enter the Black Sea in the past weeks.

On March 28, the rescue ship FS Alize passed the Bosphorus Strait to participate in NATO naval drills near Bulgaria's city of Varna.

On April 10, US destroyer USS Donald Cook also entered the sea, joined by French surveillance ship Dupuy de Lome.

The gathering of vessels in the Black Sea is apparently part of NATO's earlier announced plans to bolster defences at the eastern flank of the alliance, including at its naval borders in response to the crisis in Ukraine.

Russia, which has been undertaking reconnaissance flights over the sea for the past few days, has condemned the military buildup as a provocation.

It has also argued that some NATO countries' ships, such as USS Truxtun (which arrived in the beginning of March) are presently violating the Montreux Convention, which stipulates that vessels of non-Black Sea states might not remain in its waters for more than 21 days.