Russia will not respond in equal measure to Ukraine's decision to restrict the entry of Russian citizens, the Russian Foreign Ministry said Friday.

"It's simply scary to talk about tit-for-tat responses. If anyone tries to mirror what is happening in Kiev, it may lead to insanity, and if we talk about the national scale, then to a complete collapse," the ministry's spokeswoman, Maria Zakharova, said at a briefing.

Earlier on Friday, Ukrainian President Petro Poroshenko announced a ban of the entry for Russian men aged between 16 and 60, following days of spat with Moscow over its seizure of three Ukrainian warships near the Russian Black Sea coast.

On Sunday, three Ukrainian naval ships attempting to sail through the Kerch Strait from the Black Sea to the Sea of Azov were seized by Russian forces for allegedly violating the Russian border.

The Ukrainian Navy said that it had informed Russia in advance of the passage, while Russia said it had received no such report and the ships ignored multiple warnings by the Russian border guards.

Russia claimed that the incident was a provocation devised by the Ukrainian authorities, while Kiev urged Moscow to release captured Ukrainian soldiers.