Russia’s blockade of the Kerch Strait was announced by the Ukrainian foreign ministry.
All foreign warships will be unable to carry out military exercises in the region from next week until October.
The ministry blasted the closure in a statement, writing: “Such actions by the Russian Federation are another attempt to violate the norms and principles of international law to usurp the sovereign rights of Ukraine as a coastal state, as Ukraine has the right to regulate navigation in these areas of the Black Sea.
“They also said they view the closure as a ‘gross violation of the right to freedom of navigation’, and said Russia ‘must not obstruct or impede transit’”.
READ MORE: World holds breath as Biden expels 10 Russian diplomats
It comes as US officials cancelled a planned “freedom of navigation” exercise in the Black Sea shortly before Russia closed the strait.
A US defence official told Politico the transit was not designed to send any particularly new signal, as the navy typically conducts eight or nine such movements per year.
But in the wake of recent fighting between Ukrainian soldiers and Russian-backed separatists along the east of the country, the US decided to drop the plans.
A former Ukrainian official also told the outlet how Kyiv was disappointed at the cancelled mission, as the show of force against Russia would have been welcomed.
Dr Jade McGlynn, director of research at the Henry Jackson Society, also told the Sun Online Mr Putin is threatening to invade Ukraine as he looks to reassert Russia’s “superpower” status.
She insisted the build-up of troops and arms in eastern Ukraine is Putin “showing off” and doubts the Russian strongman would risk a full-scale conflict.
The expert then added: “Putin would rather manipulate and fool around than go into full-on war.
“War is a big risk. This is more about showing off. And showing Biden ‘don’t think you can come in and try and speak down to Russia and try and put Russia in its place because Russia is a global power’.”