Russian President Vladimir Putin has accused Ukraine's leader, Petro Poroshenko, of trying to boost his ratings ahead of 2019 elections with a naval confrontation off Crimea.
Russian FSB border guards opened fire on two Ukrainian gunboats and a tug before seizing the Ukrainian crews.
"He had to do something to make the situation more tense," Mr Putin told an investment forum on Wednesday.
Ukraine has condemned the incident as a Russian "act of aggression".
At least three of the Ukrainian sailors were wounded on Sunday as tensions spilled over in the Kerch Strait, the passage between the Black Sea and the Sea of Azov off the coast of Crimea.
The peninsula was seized from Ukraine in 2014 and annexed by Russia shortly afterwards.
The three boats were sailing from Odessa to Mariupol, a major Ukrainian port on the Azov sea, when they were confronted by four FSB vessels.
Both countries agreed to share the sea in a 2003 treaty, but Russia's decision to open a bridge across the Kerch Strait this year has exacerbated tensions.
Ukraine says Russia is deliberately blockading Mariupol and another port, Berdyansk, preventing ships from getting through the Kerch Strait.
All 24 captured Ukrainian sailors have now been given two months in pre-trial detention by a court in Russian-annexed Crimea.
"It is undoubtedly a provocation," the Russian president said, adding that it was organised by Ukraine's authorities "and, I think, the incumbent president in the run-up to the Ukrainian presidential election in March 2019".
Mr Poroshenko was languishing in fifth place according to opinion polls, he asserted, adding that the Ukrainian president's decision to impose martial law after a mere "border incident" had not even taken place at the height of the conflict with pro-Russian separatists in eastern Ukraine in 2014.
He insisted that Russia's military response was appropriate as the Ukrainians had "trespassed" into Russia's territorial waters, arguing that even before Crimea was annexed they were Russian waters.
Ukrainian officials published a map on Wednesday, placing all three Ukrainian boats just outside Crimea's territorial waters at the time they were seized.
"This political froth will die down," Mr Putin suggested, hours after Russia announced that it would send a new S-400 surface-to-air missile system to Crimea next month, to join the three already deployed this year.