Thousands protested on the streets of Budapest after scores of journalists, including three leading editors, resigned from Hungary’s main independent news site, Index.
The announcement of the mass resignation comes just two days after the company's editor-in-chief, Szabolcs Dull, was fired.
Employees had described the decision by the president of the board, László Bodolai, as "unacceptable".
On Thursday, Index held a staff meeting to request the reinstatement of Dull, which was "categorically refused".
In an open letter, journalists said the decision meant conditions for Index's independent operation were no longer in place.
"His dismissal is a clear interference in the composition of our staff, and we cannot regard it any other way but as an overt attempt to apply pressure," said Index journalists in a joint statement.
"The editorial board deemed that the conditions for independent operation are no longer in place and have initiated the termination of their employment."
Index' deputy editor-in-chief, Veronika Munk, told Euronews Hungary that Dull's sacking was a direct reason for her decision to resign.
"The sacking of Szabolcs Dull was the step that made me think I can no longer do this job freely, following professional journalistic principles," said Munk. "And I know that a lot of people among those who resigned think the same way."
Thousands took to the streets of the Hungarian capital on Friday night in a planned rally in solidarity with Index.
"It's obvious that there are political reasons behind what happened. Index was the last and only opposition media source that could criticise the government in front of big audience," one demonstrator told Euronews.
Another protester said: "It is mandatory to have a free news outlet which can publish information about both political sides. It's needed to have something like this. It's not good that all the press is supported by the government."
The website has long been a target of Hungarian Prime Minister Viktor Orban, who sought to exert more control over the country's broadcast and media industry, according to Associated Press.
In recent weeks the company said it felt its independence was "in danger" from external forces.
In 2018, Index set up an “independence barometer” to monitor editorial freedoms, after a change in ownership which led to a loss of trust between staff and management.
Last month, the barometer was changed to “in danger” from “independent” after it was confronted by management plans to reorganise the newsroom, which the editorial staff strongly opposed.
Dull released a statement on Wednesday, saying he felt it was "no accident" that the editorial staff had felt endangered.
Index's board said his dismissal was based on a failure to manage internal tensions and economic downturn.
Political journalist Daniel Renyi said he had expected mass resignations and sections of the newspaper to disappear.
He told Euronews that the firing of Szabolcs Dull was "devastating".
"It's very difficult to imagine a free Hungarian media market without the Index we know."
"Next year there might be more pressure on Hungary and Orban thinks this is the proper time to gain more influence in the independent media market," said Renyi.
Hungary is also in the midst of EU proceedings over concerns that they are violating legal standards that threaten the independence of judges and press freedoms.
European Commission Vice President Věra Jourová said she has "big concerns" and expressed support for Index employees.
“I would like to express my solidarity with the staff of Index who has been working under very difficult conditions,” Jourova said earlier this month.
In a statement, the International Press Institute has also described the board resignations as "a devastating blow to journalism in Hungary".
Index.hu has been described as the largest and most influential of the country’s remaining independent media.
"We’ve been saying this for years, written it down, shouted out loud that there are two conditions that guarantee the free, correct, and independent professional work," Veronika Munk told Euronews Hungary.
"One is that there is no external influence on the content of the site, and there is no external influence on the composition of the staff."
"They do not tell us what to publish on the site, and no one tells us from outside who to work with or not to work with."
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