Riot police firing tear gas and water cannon stormed two opposition-linked Turkish television stations and forced them off air on Wednesday, stoking deep concerns about media freedom just four days before a pivotal election.

"A dark day for Turkish democracy and freedom," declared the banner headline on the websites of the media companies targeted in the early morning raids in Istanbul.

Critics accuse the government of President Recep Tayyip Erdogan of trying to silence opponents before Sunday's vote, in which his Justice and Development Party (AKP) is widely expected to fail to regain the parliamentary majority it lost in June.

Police in riot helmets were acting on a controversial court ruling ordering the seizure of companies belonging to the Kozi-Ipek conglomerate linked to US-exiled preacher Fethullah Gulen.

Turkish authorities have launched a "terrorism" probe into the 74-year-old cleric, a one-time Erdogan ally now regarded as his arch-nemesis, and his followers.

Officers smashed through the gates of the media compound with chainsaws, according to images broadcast live on the group's television stations, Bugun and Kanalturk.

Brawls erupted outside the offices, prompting police to use tear gas and batons against demonstrators, including lawmakers from the main opposition Republican People's Party (CHP).

Several arrests were made, and an AFP photographer was punched by a plain-clothes police officer as scuffles continued throughout the day.

"We will not be silenced," chanted demonstrators.

CHP lawmakers and Bugun TV editor-in-chief Tarik Toros were seen negotiating with police in the TV control rooms before the plug was later pulled on both stations.

"This is an operation to silence all dissident voices that the ruling party does not like, including media outlets, opposition parties and businessmen," Toros said.

- 'A shameful day' -

Critics say Erdogan has become increasingly authoritarian, brooking no dissent since becoming president in August 2014 after more than a decade as prime minister.

Sunday's election is crucial for the AKP, which lost its majority in a June vote thanks to a strong performance by a pro-Kurdish party, scuppering Erdogan's hopes of changing the constitution to expand his presidential powers.

"Today is a shameful day... Everyone who made this decision and those who implemented it will have to answer for their crimes," said CHP lawmaker Baris Yarkadas.

The European Union described the developments as "worrying".

"We want to reiterate the importance of respect of the rule of law and media freedom," said Catherine Ray, spokeswoman for EU foreign affairs head Federica Mogherini.

"We expect this election to be in line with international and democratic standards."

The US State Department called the reports out of Turkey "concerning".

"We continue to urge Turkish authorities to respect not just media freedom, but the political process, which includes... a vocal opposition," State Department spokesman John Kirby said.

- 'Politically motivated' -  

An Ankara court on Monday appointed a board of trustees to manage the Koza-Ipek group, seizing its 23 companies as part of a crackdown on Gulen's followers.

The Ankara chief prosecutor's office said the seizure was linked to an investigation into the conglomerate on suspicion of "terror financing", "terror propaganda" and other offences related to Koza-Ipek's support for Gulen's Hizmet (Service) movement.

Koza-Ipek CEO Akin Ipek denounced it as "politically motivated", saying the government had failed to find any illegal activity during inspections of the company, whose businesses range from media to mining, insurance to healthcare and tourism to food.

- Shares tumble -

Shares in its listed companies, which include Turkey's biggest gold miner, sank on the Istanbul bourse on Wednesday, wiping several hundred million dollars off their market value.

Rights groups have expressed growing alarm about the state of press freedom under Erdogan, with about 20 journalists detained on a variety of charges.

Ahead of the election, the government is taking "exceptional measures to silence critical media and crack down on perceived opponents," said Emma Sinclair-Webb of Human Rights Watch in Turkey.

"Not since the days of the 1980 military coup have there been such dramatic moves to close down and prevent scrutiny of power," she said in a statement.

There have also been a string of prosecutions against journalists, artists and even schoolboys accused of "insulting" the head of state.

Erdogan accuses Gulen of operating a "state within a state" in Turkey and trying to topple him by persuading allies in the police and judiciary to launch a vast probe into government corruption in December 2013.

Turkey's authorities responded by purging both the police force and judiciary of pro-Gulen elements and arresting editors and businessmen.

The cleric, who left for the United States in 1999 to escape charges of anti-secular activities by the government of the day, denies the allegations.

He is set to be tried in absentia on January 6.
Source: AFP