Manila, Philippines • A journalist critical of Philippine President Rodrigo Duterte was arrested Wednesday and will spend the night in detention in what critics are calling the latest assault on the free press in the Philippines.

An arrest warrant for "cyber libel" was served to Maria Ressa, head of the Rappler news site, at her office by plainclothes officers of the National Bureau of Investigation just before 5 p.m., the cutoff time for courts to process bail payments.

"These legal acrobatics show how far the government will go to silence journalists, including the pettiness of forcing me to spend the night in jail," Rappler quoted Ressa as saying.

Her lawyers attempted to process bail at a night court in Manila, but their efforts were rejected by a judge. Ressa will spend the night at the National Bureau of Investigation, Rappler reported.

Ressa was named Time magazine’s Person of the Year in 2018 for her work, an honor she shared with several other journalists around the world. Before founding Rappler in 2012, Ressa was CNN bureau chief in Manila.

She had been scheduled to give a talk on press freedom at the University of the Philippines the evening she was arrested.

The Philippines' Justice Department had recommended last week the filing of charges against Ressa and former researcher Reynaldo Santos Jr. under the cyber libel law over a story published in May 2012. The law, however, wasn't passed until September 2012, months after the alleged crime was committed.

The complaint was filed by businessman Wilfredo Keng earlier this year, according to Rappler, reportedly because the story mentioned his alleged links to illegal drugs and human trafficking.

Justice Secretary Menardo Guevarra said that the arrest was part of standard procedure and that Ressa was free to post bail.

"This charge, as well as the tax evasion case, has nothing to do with press freedom," Guevarra told The Washington Post in a text message. "An outfit like Rappler is not one that could be easily intimidated by defamation cases, which are normal hazards of the journalists' profession."

In December, the award-winning, 55-year-old journalist had to post bail for charges of tax evasion. The government accused her company of sidestepping laws on foreign ownership.

In a statement, Rappler said that Ressa did not even edit the story in question.

"This is a dangerous precedent that puts anyone - not just the media - who publishes anything online perennially in danger of being charged with libel," the company said. "No one is safe."

Employees of Rappler, a digital newsroom of some 100 staffers, took to social media to broadcast the tension in the newsroom during the arrest. In a video posted by multimedia reporter Aika Rey on Facebook, an unidentified officer tells her to stop recording.

"We're doing our job. I think this shouldn't be posted anywhere else, because that's basically our weapon: our identity. Do you get that?" he said. "Can you stop doing what you're doing now? Is it okay? Tell this to your colleagues. Because, definitely, if we see our faces on the Net, you'll be sorry. You've been warned. We'll go after you."

Rappler has distinguished itself for its hard-hitting reporting targeting the abuses by Duterte's government, particularly his campaign against drug dealers that has resulted in the deaths of thousands often through extrajudicial methods. Duterte has repeatedly labeled the site "fake news."

The National Union of Journalists of the Philippines slammed the arrest as "a shameless act of persecution by a bully government."

“It is clear this is part of the administration’s obsession to shut Rappler down and intimidate the rest of the independent Philippine media into toeing the lines,” it said. “Even as we are certain they will hold the line, we . . . urge all colleagues who value the work we do and the independence essential to it to circle the wagons and resist this blatant assault on our right and liberties.”