Turkish police raided Tuesday the main offices and broadcast centre of IMC TV, a key opposition news channel based in Istanbul, cutting the broadcast.
Also, Ozgur Radyo, a pro-Kurdish radio station also based in Istanbul, was shuttered and 17 people were arrested during the police operation, the private Dogan news agency reported.
Journalists and politicians were using social media to broadcast the crackdown over the Internet. IMC also confirmed the raid by armed police on its Twitter account.
Videos showed journalists and their supporters protesting the move at the stations and shouting slogans, including: "Free media will not be silenced."
IMC was among more than 20 channels that Turkey's broadcasting authority ordered shut last week, drawing strong condemnation from press freedom groups like the Committee to Protect Journalists. The government alleged the stations carried "terrorist propaganda."
The measure affected mostly Kurdish and leftist broadcasters, including a children's channel that showed cartoons in the Kurdish language.
"The right to information has been hindered. This is anti-democratic and unacceptable," Hamza Aktan, news editor of IMC TV, told dpa.
Since the failed July coup, Turkey has implemented a state of emergency. The government blames the putsch on Fethullah Gulen, a US-based preacher, and has shut dozens of media outlets affiliated with his movement.
However, the government has also increasingly moved against Kurdish activists, politicians and media, alleging they have ties to militants.
Even prior to the coup, Turkey was moving against media outlets critical of the government, including the Zaman daily, considered the largest daily, which was part of the Gulen movement.
With increasing pressure on media outlets in Turkey, key channels failed to report on the latest raids on IMC and Ozgur Radyo.
Some 100 journalists are jailed in Turkey, according to the European Federation of Journalists.