The authoritarian country leans on a raft of broadly-worded national security laws to detain dissidents and dole out lengthy jail terms, drawing frequent criticism from rights groups and Western governments.

On Friday, a court in northern Thai Binh province convicted activists Tran Anh Kim, 67, and Le Thanh Tung, 48, of attempting to overthrow the government by "setting up a democratic force for revolution," said Tung's lawyer Vo An Don.

Kim, a former soldier, was handed 13 years while Tung was sentenced to 12.

Both were re-arrested last year only several months after they had finished jail terms for national security offences.

Tung's lawyer told AFP after the trial that his client had been "wrongly charged".

"It was just an intention. Vietnamese laws do not ban people from having the intention of setting up associations," he said.

Kim's lawyer Tran Thu Nam also slammed Friday's trial as "not objective".

Both will also be placed under probation for five years after they serve their sentences, the lawyers added.

All newspapers and television channels are state-run in Vietnam, which ranks 175 out of 180 on Reporters Without Borders' latest press freedom index.

Bloggers and activists have taken to social media in recent years to voice anti-government views but are routinely subject to arbitrary detention and jail time.

According to Amnesty International, at least 45 people behind bars in Vietnam are "prisoners of conscience".

Agence France Presse - December 16, 2016