"The MFA [Ministry of Foreign Affairs] and Border Service should address Ukrainians with a request to refrain from visiting Crimea due to numerous provocations committed against Ukrainian citizens. It is also my personal request," Poroshenko said, as quoted by the presidential press service.
On Wednesday, Russia's Federal Security Service (FSB) said that it had uncovered a spy ring organized by the Ukrainian Defense Ministry in Crimea, detaining both Russian and Ukrainian nationals involved in preparing terrorist attacks on the peninsula. An FSB officer died as a result of a shootout during the raid.
The Federal Security Service also said it had prevented two overnight attempts by Kiev-organized terrorist groups from entering Crimea overnight into August 8, in which one Russian soldier was killed.
Russian President Vladimir Putin called the incidents a "very dangerous game" adding that Ukraine's authorities had resorted to terrorism instead of looking for peaceful solutions to the conflict in the east of the country.