The European Union has called on Russian authorities to stop targeting Tatars in Russian-annexed Crimea.
A court in the Crimean capital, Simferopol, said on March 29 that since March 27, 23 Crimean Tatars had been arrested and placed in pretrial detention until May 15, on charge of belonging to the banned Hizb ut-Tahrir Islamic group.
An EU spokesperson said in a March 30 statement that the European Union expected "all illegally detained Ukrainians to be released without delay."
"The European Union expects the Russian Federation to end these practices and to take all necessary steps to ensure that human rights and fundamental freedoms can be exercised by all in Crimea, without discrimination on any grounds," the statement added.
Since Russia seized the Ukrainian peninsula in 2014, Russian authorities have prosecuted 31 Crimean Tatars for allegedly belonging to Hizb ut-Tahrir.
In February, the branch of Russia's Federal Security Service (FSB) in the Black Sea region launched probes against eight alleged members of the group accused of plotting to seize power in Crimea.
Hizb ut-Tahrir is a global organization based in London that seeks to unite all Muslim countries into an Islamic caliphate.
The group can operate legally in Ukraine.
However, Russia's Supreme Court banned it in 2003, branding its supporters "extremists."
Rights groups and Western governments have denounced what they describe as a campaign of repression by the Russian-imposed authorities in Crimea who are targeting members of the Turkic-speaking Crimean Tatar community and others who have spoken out against Moscow's takeover of the peninsula.
Russia took control of Crimea from Ukraine in March 2014 after sending in troops, seizing key facilities, and staging a referendum dismissed as illegal by at least 100 countries. Moscow also backs separatists in a war against government forces that has killed some 13,000 people in eastern Ukraine since April 2014.