Russia said Wednesday a Dutch court decision to transfer a collection of Crimean gold to Ukraine was politically motivated and "set a dangerous precedent," as Moscow opened a criminal probe into the case.
An Amsterdam court ruled this week that the pieces, dubbed "Scythian Gold" and loaned to the city's Allard Pierson Museum just before Moscow annexed Crimea in 2014, should be handed over to Ukraine.
The ruling was hailed in Kiev as a victory.
In a statement, Foreign Ministry spokeswoman Maria Zakharova accused the Dutch judges of being "guided exclusively by political motives."
She said the artefacts were part of the "cultural and historical heritage of the peoples of the Crimean peninsula."
Zakharova said Moscow had hoped that "at least the culture sphere would stay out of politics."
Earlier Russia's Investigative Committee said it had instructed investigators in the Russian-controlled peninsula to probe "the non-return of cultural items belonging to the Republic of Crimea."
The head of the committee, Alexander Bastrykin, had also asked for investigators to work with Moscow's Foreign Ministry to "thoroughly study" the case.
Ukraine's President Volodymyr Zelenskiy this week said the "long-awaited victory" to return the treasure, was a "fair decision."
"We always regain what's ours. After the 'Scythian gold', we'll return Crimea," he said on Twitter after the ruling.
The Kremlin warned Wednesday that the comments "could have negative consequences."
The rich collection spans the second century BC to the late medieval era, when Crimea was at the crossroads of ancient trade routes through an area dominated by the Scythian people.
The fate of the gold has been subject to legal wrangling since four museums on the peninsula launched a joint challenge seven years ago to have them returned.
In 2016, a lower Dutch court ruled that the treasures were part of Ukraine's cultural heritage and must be returned to Kiev — not to the museums that launched the petition — on the grounds that Crimea was not considered a sovereign state.
The Crimean museums appealed the judgement. But on Tuesday, the Dutch court of appeal ruled that the gold should be held by Ukraine "pending stabilization in the Crimea."