The Philippine government faced a barrage of protests on Wednesday as a cybercrime law went into effect that critics said had imposed dictator-style monitoring and policing of the Internet.
Major news outlets, bloggers, rights groups and other critics turned their social media profile pages black to express outrage over the law, which could see people face long jail terms for posting defamatory comments online.
Thousand of furious tweets were posted on Twitter, with the hashtag #notocybercrimelaw becoming the top trend on the microblogging site in the Philippines on Wednesday.
"This law works against ordinary netizens and disregards, among other things, our right to privacy and freedom of expression," tweeted Noemi Dado, a prominent Manila blogger who edits a citizen media site called Blog Watch.
Senator Teofisto Guingona, one of the few members of parliament who opposed the bill that President Benigno Aquino signed into law last month, also stepped up his campaign to have it overturned.
"The implementation of the law... will take back our citizens to the Dark Ages where freedom of speech and expression were not recognised," he said in a statement.
Many provisions of the cybercrime law aim to fight a range of online crimes not deemed controversial, such as fraud, identity theft, spamming and child pornography.
However one provision makes any libellous comments posted online a criminal offence, with a penalty of up to 12 years in jail, much tougher than for traditional media.
Equally controversially, the Department of Justice also now has the power to close down websites and monitor online activities, such as email, instant messaging or video chats, without a warrant.
The Philippines has had one of Asia's most vibrant democracies and robust media environments since a people power revolution led by Aquino's mother toppled dictator Ferdinand Marcos in 1986.
Social media has also flourished in recent years. Nearly a third of the population of 100 million people has access to the Internet, and 96 percent of Filipino web users use Facebook, according to industry figures.
But critics of the law have said it echoes tactics to silence and monitor dissenters employed by Marcos when he imposed martial law in the 1970s.
"The Cybercrime Prevention Act of 2012 is the worst assault on free expression since Ferdinand Marcos declared martial law," Luis Teodoro, a journalism professor at the University of the Philippines, wrote in a blog.
Joaquin Bernas, a Jesuit priest and lawyer who helped draft the country's post-dictatorship constitution in 1987, voiced similar sentiments in an article published this week outlining his concerns about the law.
"There are very valid reasons for being frightened by this," Bernas wrote in the Philippine Daily Inquirer, highlighting the government's new authority to monitor and close down suspect websites without a warrant.
"I for one recall the law on search and seizure in effect during the past martial law period."
Aquino's spokespeople have repeatedly defended the law as necessary to fight cybercrime, while insisting his administration would uphold freedom of speech online.
They also said a spate of hacking on government websites in protest over the law highlighted the need for it.
But amid the backlash, some of the politicians who voted for the bill said they would were willing to get rid of the controversial provisions.
"At the end, we should be humble enough to admit we may have made a mistake and we can still amend the law," said Congressman Sonny Angara, whose father, Senator Edgardo Angara, authored the cybercrime bill.
Critics have also filed petitions to the Supreme Court calling on it to rule that the law is unconstitutional.