On Sunday, Russian military exercises will begin in the Black Sea and the Sea of ​​Azov south of Ukraine.

Russia has issued warnings about missile and artillery exercises.  

Ukrainian Foreign Minister Dmytro Kuleba says the exercises will take place on such large areas that maritime traffic will be impossible in practice.

Ukrainian Defense Minister Oleksii Reznikov accuses Russia of blocking international water in a post on twitter.

The crisis visible from the terrace

The Black Sea and the connection with the Mediterranean via the Bosphorus are Ukraine's most important export route.

A significant proportion of the world's consumption of wheat and cereals is shipped from here. 

 - Maritime traffic is like a giant puzzle that reveals signs in international politics, says ship enthusiast Yöruk Isik.  

From his terrace in Istanbul, he can follow every single ship that crosses the strategically important Bosphorus Strait, the only connection between the Black Sea and the Mediterranean. 

- This crisis has appeared before my eyes in my own residential area.

Russian demonstration of power

In the past week, Yöruk Isik has photographed six Russian warships passing through the Bosphorus.

They have sailed from Russian naval bases in the Kaliningrad Baltic Sea and the Kola Peninsula in the Arctic Ocean.  

- When they pass the Bosphorus, there is no longer any doubt that they are on their way to the Black Sea, says Yöruk Isik. 

To monitor the movements of military ships, physical observations are required because they cannot be digitally tracked.

Therefore, ship enthusiasts surveys play an important role.  

Yöruk Isik draws the same conclusion as many international assessors.  

- The reinforcements seal Russia's dominance in the Black Sea.

The intention is to increase military pressure on Ukraine.