Accompanied by much criticism from the West, Russia plans to close off several areas of the Black Sea from Saturday.
Shipping through the Kerch Strait by the Crimean peninsula will not be affected by the closure, which is planned to last until October 31.
Nevertheless, the Russian plan has been criticized by the European Union, Ukraine and NATO.
Among other things, there are concerns that the rights of passage enshrined in the United Nations Convention on the Law of the Sea could be restricted and international shipping impeded.
Russia stressed that the sea areas concerned were in Russian territorial waters. However, Russia’s claim to the areas near Crimea, which it annexed in 2014, has not been recognized.
Russia had recently held a manoeuvre in Crimea, criticized by Ukraine as an act of aggression. On Friday, the withdrawal of the additional troops deployed there began.