Ukraine on Friday barred Russian men aged 16-60 from entering the country following the imposition of martial law amid fears in Kiev of a Moscow-backed land invasion.
According to Kiev, an exception would be made for exceptional cases such as funerals, the BBC reported. Russia said it was not planning retaliatory measures.
Martial law has been imposed in 10 Ukrainian regions, the majority bordering Russia, till December 26.
Ukrainian President Petro Poroshenko announced the move following a meeting with top security officials on Thursday as a response to flaring tensions in the region after Russia fired on and seized three Ukrainian Navy vessels and detained 24 sailors in a geopolitically sensitive area of the Black Sea on November 25.
"Ukraine has imposed a restriction on the entry of citizens of the Russian Federation aged 16 to 60 so that Russia cannot create 'private' armies in Ukraine, which are actually representatives of the Russian armed forces," Poroshenko said in a statement shared on social media.
Poroshenko had also urged NATO to deploy warships to Sea of Azov shared by the two nations.
The Kerch Strait has become a geopolitical flashpoint since Russia completed the multibillion-dollar Kerch bridge, which now connects the Crimean Peninsula with mainland Russia.
A court in Crimea, a territory that Russia annexed from Ukraine in 2014, ordered the seamen into provisional detention pending trial where they could face charges of illegally crossing into Russian territory, Efe news reported.
The detainees have since been transferred to Moscow.
Russian President Vladimir Putin said the Ukrainian officers purposely provoked Russian forces in the strait, but Ukraine maintains its passage was illegally blockaded by Russia.
It was the most dangerous clash at sea off Crimea since Russia annexed the Ukrainian peninsula in March 2014.
German Chancellor Angela Merkel earlier said that there was no military solution to the conflict between Moscow and Kiev and she held Putin responsible for it.
US President Donald Trump also called off his meeting with Putin over Moscow's seizure of Ukrainian ships.
(With inputs from agencies.)