A Ukrainian filmmaker was sentenced to 20 years in a strict-regime prison colony on terror charges by a Russian military court on Tuesday.
Oleg Sentsov, 39, was convicted for allegedly carrying out arson attacks on pro-Kremlin party offices in Crimea after it was seized by Russia last March, and plotting further attacks, including blowing up a Lenin statue in the peninsula's main city of Simferopol.
His fellow Ukrainian co-defendant Alexander Kolchenko was sentenced to 10 years for allegedly taking part in attacks.
Acclaimed filmmakers from across the globe, including Spain's Pedro Almodovar and Britain's Mike Leigh, have written to Russian President Vladimir Putin expressing concern over Sentsov's prosecution.
Russian film director Andrei Zvyagintsev, whose latest film "Leviathan" won a Golden Globe, wrote in a letter published in Novaya Gazeta newspaper on Monday that it was "monstrous to jail a young man, a promising filmmaker".
Zvyagintsev called for Russia to "either release him or only try him for what you can prove irrefutably".
The up-and-coming director had his debut feature "Gamer" shown at the Berlin Film Festival in 2012.
As the sentence was read, Sentsov defiantly flicked a victory sign and he and Kolchenko sang the Ukrainian national anthem inside their glass enclosure.
Ukrainian President Petro Poroshenko, who had called for the men's immediate release, wrote on Twitter in Ukrainian: "Hold on, Oleg. The time will come those who organised the trial against you will find themselves in the dock."
Sentsov and Kolchenko have been held behind bars in Russia since May last year.
The case was heard in a military court in the southern city of Rostov-on-Don, one of only two courts in Russia authorised to hear terrorism cases.
Prosecutors last week asked for Sentsov to be jailed for 23 years and for Kolchenko, a pro-Kiev activist who opposed Russia's annexation of Crimea, to be sentenced to 12 years.
The men were tried as Russians, despite never having applied for citizenship. Both pleaded not guilty.
In his final trial statement, Sentsov condemned Moscow's rule.
"Your propaganda is very good, but there are also people like you who understand very well that there are no 'fascists' in Ukraine, that Crimea was taken illegally and that your troops are in Donbass," he said of the conflict zone in eastern Ukraine.
Defence lawyer Dmitry Dinze told AFP when the trial started last month that he expected a guilty verdict but hoped the men could be returned to Ukraine in a prisoner exchange.
The men are among 11 Ukrainians held in Russian prisons whom Kiev considers to be political prisoners, according to Ukrainian Foreign Minister Pavlo Klimkin.
These include military pilot Nadiya Savchenko who is currently on trial over the deaths of two Russian journalists in eastern Ukraine.
Russian President Vladimir Putin has denied that Sentsov and Savchenko are prisoners of war.
Amnesty International condemned the case as a "show trial" that was "rife with irregularities", in a statement released ahead of the verdict.
It has called for the men to be tried in a civilian court and for Russia to "investigate all allegations of torture and other ill-treatment of defendants and witnesses in the case".
Defence lawyers say witnesses have been tortured to produce testimony implicating Sentsov and Kolchenko in activities involving Ukrainian far-right organisation Right Sector, which is banned in Russia.
Two prosecution witnesses have already been sentenced to lengthy terms in connection with the case after refusing to testify in court.