Turkish Foreign Minister Mevlut Cavusoglu has described the situation in the Ukrainian peninsula of Crimea, which was annexed by Russia in March 2014, as "unacceptable."

Addressing a news conference in Lithuania on April 3, Cavusoglu said that the Crimean people, particularly Turkic-speaking Tatars, have been "oppressed."

He added that Turkey will send an "informal mission to observe human rights violations in Crimea soon."

Turkey has close cultural bonds to Crimea's indigenous Muslim Tatars, who bitterly opposed Russia's seizure of the Black Sea peninsula last year.

Ankara did not join Western sanctions over the annexation, but Cavusoglu insisted Turkey would "never recognize the illegal annexation" of the peninsula.

Cavusoglu's statement comes two days after Crimea's only Tatar-language television broadcaster, ATR, was shut down after it failed to register the channel with Russian authorities by a March 31 deadline.

Russia's media oversight body Roskomnadzor, citing technicalities, rejected several attempts by ATR to register for a Russian broadcast license.

Several ATR affiliates were also shut down.

The United States on April 1 condemned the media outlets' de facto closure, calling it the "latest in a string of actions that undermine freedom of expression in Crimea."

U.S. State Department spokeswoman Marie Harf said the closure followed a "yearlong crusade to silence the Crimean Tatar population and others who oppose Russia's occupation."

She noted Crimean Tatars have been singled out and subjected to a "pattern of discrimination, intimidation, and persecution."

Rights watchdog Amnesty International has called the refusal to register ATR a "blatant attack on freedom of expression, dressed up as an administrative procedure," and "a crude attempt to stifle independent media, gag dissenting voices, and intimidate the Crimean Tatar community."

Activists, community leaders, and rights groups say Crimean Tatars have faced discrimination, pressure, and abuse for their opposition to Russia's annexation of the peninsula.

With reporting by AFP and Reuters