Ukraine has protested to Russia after a leather-clad President Vladimir Putin visited the annexed Crimean peninsula to attend a bikers' festival.
Its foreign ministry described Saturday's visit as a "blatant violation of Ukraine's sovereignty".
Ukraine said attempts by Moscow and its media to present such visits as routine were "pathetic".
Crimea was annexed from the Ukraine in 2014, triggering a wave of ultra-patriotism in Russia.
The Night Wolves, a right-wing nationalist bikers' group close to President Putin, were prominent supporters of the annexation.
This year, they held their annual show in Sevastopol, the peninsula's largest city.
Mr Putin - who arrived at the event astride a motorbike - appeared to be the guest of honour, with bikers thronging around the Russian leader, hoping to get a selfie.
But the visit comes as Mr Putin faces growing disquiet at home.
Up to 60,000 people thronged the streets of the Russian capital on Saturday in an authorised demonstration to demand "fair" municipal elections in September.
Some tried to reach the presidential administration building in a later unsanctioned protest and hundreds were arrested.