Kiev - Ukraine on Friday announced a travel ban for Russians aged between 16 and 60 years ago, while it closed foreign citizens'' entry to Crimea.

Ukrainian President, Piotro Poroshenko, who imposed martial law after a denounced provocation on Sunday against Russia in the Black Sea and near the Kerch Strait, published the measure on his Twitter account.

Poroshenko said that the decision responds to the need to prevent the alleged formation by Moscow of detachments of 'soldiers of war' to finalize the mission started in 2014.

After the February 2014 coup d'Etat against President Viktor Yanukovych, Crimea carried out a referendum in March of that year, in which its population approved the sovereignty of the territory and the return to Russian jurisdiction, while the right-wing government launched operations against the Donbass region.

Moscow recalls that it has strong evidence of the organization by Kiev of the aforementioned provocation with the use of three small warships, which only stopped when force was applied against them.

The Ukrainian Border Service stated that it would prevent, as of Friday, the passing of all foreigners to Crimea.

Andrei Demchenko, spokesman of the aforementioned body, said the measure sought to stop the entry to Ukraine of people with possibilities of carrying out destabilization actions.