Russian law enforcement officials on Monday raided the premises of Tatar television station ATR in Crimea, the Black Sea peninsula Moscow annexed from Ukraine last March, triggering criticism from the OSCE, the European rights watchdog.
Crimean Tatars, a large ethnic minority in the region, mainly opposed the annexation and have come under pressure to align themselves with the new authorities ever since.
Russia's federal Investigative Committee, which answers directly to President Vladimir Putin, who describes Crimea as "sacred" to Russia, said it was searching ATR's offices as part of a probe into the death of two locals during a rally a year ago.
An ATR representative in the regional capital Simferopol said the search started at 11 a.m. and was still going on at 5 p.m., shutting down most of the channel's broadcasting.
The Organization for Security and Cooperation in Europe, or OSCE, said ATR must be allowed to resume broadcasting as soon as possible.
"This practice of intrusion on free and independent media cannot be tolerated in the OSCE region," the organization's representative on freedom of the media, Dunja Mijatovi, said in a statement.
The Investigative Committee said it believed ATR had recordings of a rally in Crimea on Feb. 26, 2014, during which state officials and members of a pro-Russian group were injured. Two locals died as a result, it said.
Russian troops wrested the Black Sea peninsula away from Kiev after street protests in Kiev ousted Moscow-backed president Viktor Yanukovych.
Crimea's annexation threw ties between Moscow and the West into disarray, with the European Union and the United States slapping sanctions on Russia and stepping up pressure on the Kremlin as violence spread to east Ukraine in April last year.
The West says Russia is the driving force behind a separatist rebellion there, an accusation Moscow denies. More than 5,000 people have been killed in east Ukraine, where pro-Russian rebels announced a new offensive last week.