Russian authorities on Wednesday shut down a television channel serving Crimean Tatars, an ethnic group that opposed Moscow's seizure of Crimea, sparking concern in Ukraine and the West.
ATR television channel was forced off air after Russia's state media regulator refused to give it a broadcasting licence.
The move caused outrage in Kiev, with Ukrainian President Petro Poroshenko tweeting: "You can shut down the channel but you cannot stop the Crimean Tatars' desire for freedom and the truth!"
A Muslim minority on the mostly Russian-speaking peninsula, the Tatars were deported en masse by Stalin to Central Asia during World War II, with nearly half dying of hunger and disease.
They only returned to Crimea at the end of Soviet rule and the 300,000-strong community was gradually gaining more rights in recent years.
The closure of a media outlet that served the minority group for nearly a decade is only the latest salvo in Russia's crackdown on the largely pro-Ukrainian community that has also included raids on the channel's offices.
"We stopped broadcasting at midnight," the channel's deputy general director, Lilya Budzhurova, told AFP.
Budzhurova, who also reports for Agence France-Presse, said the staff of more than 200 people have refused to give up.
"This is not the end," she said. "If someone thinks that they can kill the channel -- which is one of a kind in the world -- then they are mistaken."
She said the closure of the channel was a major blow for a community.
"People are awfully depressed," she said, adding that some 150-200 activists gathered in front of the channel's offices Tuesday night in a show of support.
The owner of the ATR media holding, Lenur Islyamov, said the closure was a mistake and could radicalise the community.
"It turned out that our homeland does not need us."
Authorities also shut down several other media of the same holding including a children's TV channel and two radio stations.
Islyamov, the holding's owner, said they were looking for ways to continue operations but ruled out leaving the peninsula.
"For us this option would be unacceptable because that would amount to cultural deportation."
Since the annexation of Crimea the Russian authorities have detained Tatar activists, evicted them from their local assembly and accused ATR, which broadcasts in Russian, Tatar and Ukrainian, of extremism.
"The channel's main crime is that they did not lie," Mustafa Dzhemilev, the Crimean Tatars' spiritual leader and a prominent Soviet-era dissident, told AFP.
"These are trying times for us," added Sevgil Musayeva-Borovyk, a Crimean Tatar who edits Kiev-based online newspaper Ukrainska Pravda.
Writing on Facebook, Musayeva-Borovyk said ATR was "the only Crimean Tatar channel which spoke about the culture and history of our people, which broadcast in our native language that unites us."
The Organisation for Security and Cooperation in Europe's media freedom representative, Dunja Mijatovic, condemned "censorship of free and independent voices in Crimea."
The United States's top diplomat for Europe, Victoria Nuland, this month slammed what she called a "reign of terror" by authorities in Crimea.
Moscow has denied any discrimination against the Tatars.
A pro-Kremlin senator accused the media outlet of seeking to destabilise the peninsula.
"Even back when Crimea was part of Ukraine, this channel could be described as Russophobic and anti-Russian," Sergei Tsekov told radio station Echo of Moscow.