Police in the Indian capital, Delhi, have raided the homes of several prominent journalists and authors in connection with an investigation into the funding of news website NewsClick.
Police have seized mobile phones and laptops of those they raided on Tuesday morning.
Officials are reportedly investigating allegations that NewsClick got illegal funds from China - a charge it denies.
Critics say the move is an intentional attack on press freedom.
Started in 2009, NewsClick is an independent news and current affairs website which is known to be critical of the government. In 2021, it was raided by tax authorities on allegations of breaking India's foreign direct investment rules.
The co-ordinated raids at 30 locations on Tuesday are some of the largest and most extensive on India's media in recent years. Opposition leaders have called it the Bharatiya Janta Party (BJP) government's "fresh attack on the media".
But Information and Broadcasting Minister Anurag Thakur has denied any involvement of the government, saying that the investigative agencies were merely doing their job.
Among those who have been searched are NewsClick editor Prabir Purkayastha, journalists Abhisar Sharma, Paranjoy Guha Thakurta, Aunindyo Chakravarty, Bhasha Singh, popular satirist Sanjay Rajoura and historian Sohail Hashmi. Some of them have been taken to police stations for questioning.
Searches were also under way at the website's office in Delhi, news agency ANI reported.
In Mumbai city, activist Teesta Setalvad's house was also searched. Ms Setalvad has long fought for victims of the deadly 2002 riots in Gujarat state and has written articles critical of the government for Newsclick.
A source close of Mr Purkayastha told the BBC that more than 15 policemen arrived at his home at 06:30 local time (01:00GMT).
"They did not produce any warrants or paperwork, questioned him for several hours and took away all the electronic devices they found at home," they said. Later, news agencies showed him being taken away by the police in a vehicle.
Mr Rajoura's lawyer Ilin Saraswat said the comedian was raided at the same time and that police took away his laptop, his two phones, some DVDs of his old work and some documents.
"The police said that Mr Rajoura is not named in the current investigation, but since he has worked with the website, he will be interrogated. We have not been provided a copy of the police complaint," he added.
The police have not yet commented on the raids and Delhi Police spokesperson Suman Nalwa declined the BBC's request for comment - she said she would "share the details when she gets them".
According to reports, the raids are in connection with a case registered against NewsClick in August after a New York Times report alleged that the website had received funds from an American millionaire to spread "Chinese propaganda".
It claimed that Neville Roy Singham worked closely with the "Chinese government media machine" and used his network of non-profit groups and shell companies to "finance its propaganda worldwide".
A case was reportedly registered against the website under UAPA, a draconian anti-terror law that makes it nearly impossible to get bail. NewsClick has strongly denied all the charges as false.
All the people who were raided have been associated with NewsClick - some are employees while others have worked on freelance projects.
Prabir Purkayastha, the founder and editor-in-chief of the website, is the author of a number of books. During the 1975 Emergency - when civil liberties were suspended - he was jailed along with several opposition politicians.An engineering major, he is also a science activist and a founding member of the Delhi Science Forum, a non-profit that works in the areas of science and technology policies
Bhasha Singh is an activist and journalist who has reported extensively on manual scavenging and farmers' suicides in northern India. On Sunday, she attended a national conference by the All India Progressive Women's Association where she accused the the government of being anti-women.
A day later, she appeared in a Newsclick video, expressing concern over the increasing trend of praising Gandhi's assassin Nathuram Godse by members of India's governing BJP party.
Abhisar Sharma is well-known video journalist with over 1.8m followers on X and nearly 3m subscribers on his YouTube channel. He worked for BBC Hindi before moving on to work as a Hindi presenter at the NDTV news channel.
Mr Sharma is known for his critical views of the government. One of his last videos covered widespread protests by government employees against the new pension scheme.
Sanjay Rajoura is a popular stand-up comedian and part of the comedy-music trio Aisi Taisi Democracy (Democracy be damned). Mr Rajoura is known for biting political satire that often critiques the ruling party. His work spans topics of caste, masculinity, freedom of speech and fake news. The comedian has also worked in Bollywood, acting in films like City of Dark and The Seal.
Sohail Hashmi is a historian, activist and filmmaker who's been holding talks and heritage walks on Delhi's history for over a decade. This month, Sahmat, a trust run by him, is organising programmes to observe the 75th anniversary Mahatma Gandhi's assassination.
The police are yet to share the complete details of their investigation - and it's not clear when they will do so - but the raids have sparked outrage in the country.
Several associations of journalists and news organisations criticised the police action, which they called "another instance of the government's pattern of arbitrary and intimidatory behaviour".
The Press Club of India said it was "deeply concerned" about the raids and urged the government to "come out with details" about the case.
In a joint statement, the National Alliance of Journalists and Delhi Union of Journalists accused the government of targeting NewsClick for "their coverage of the issues of workers and farmers".
Since Prime Minister Narendra Modi came to power in 2014, a number of media outlets have been investigated by the government for alleged financial impropriety, raising fears about press freedom in the world's largest democracy.
Earlier this year, tax officials searched BBC offices in India, questioning staff about the organisation's business operations in the country. The searches in Delhi and Mumbai had come weeks after the broadcaster aired a documentary in the UK critical of Mr Modi's role in the 2002 Gujarat riots.
Tax officials also accused the Dainik Bhaskar newspaper of tax evasion in 2021 after its critical coverage of the government's handling of the Covid-19 pandemic.
Reporters Without Borders, an advocacy group for journalists, has placed India at 161st place in its press freedom rankings this year. It said the situation in the country has deteriorated from "problematic" to "very bad" and compared it with Tajikistan (at 153rd) and Turkey (at 165th).
Additional reporting by Meryl Sebastian in Kochi