Vietnam on Tuesday jailed six people on various security and anti-state charges in three separate cases, in one of the harshest days of sentencing in the communist country where dissidence is routinely quashed.

The one-party state has long jailed its critics, though a hardline leadership in charge since 2016 has ushered in an increase in arrests and convictions of activists, dissidents and bloggers.

On Tuesday, six people were sentenced to jail in various trials across the country.

The longest was for Russian-educated activist Pham Van Diep, who was sentenced to nine years for “making, storing and spreading anti-state material,” according to his lawyer.

Diep was accused of protesting and posting on Facebook after an environmental disaster in 2016 that killed tonnes of fish in central Vietnam, and also for railing against a controversial cybersecurity bill.

His attorney said he was merely expressing his opinions and did not break the law.

“This was a pre-arranged verdict,” Ha Huy Son said after the trial in central Thanh Hoa province, adding that Diep would file an appeal.

In another court case in southern Bac Lieu province, Nguyen Chi Vung was sentenced to six years in jail for anti-state propaganda.

Vung was accused of using Facebook to livestream anti-communist content in posts that received thousands of shares, according to the official Vietnam News Agency.

He was also accused of trying to “incite” people on Facebook to join protests, VNA added.

In a third case, in southeastern Dong Nai province, four people were jailed for between two and three years on “security disruption” charges, according to state press.

They were accused of plotting protests and planting explosives, though no evidence was provided.

Protests of any kind are banned in Vietnam, where all media is run by the state and blogs routinely scrubbed from the web.

Vietnam ranks 176 out of 180 countries on Reporters Without Borders’ 2019 World Press Freedom list, ahead of China, Eritrea, North Korea and Turkmenistan.

Last week police arrested high-profile journalist Pham Chi Dung, an outspoken former communist party member who went on to found the Independent Journalists Association of Vietnam.

There are scores of political prisoners behind bars in Vietnam, many of whom were jailed for posting content on Facebook.

The social media site has become a battleground between activists and authorities, especially since a cybersecurity law was passed last year.

Though not yet implemented, the bill requires internet companies like Facebook and YouTube to hand over user data and remove content if requested by the government to do so.

AFP