Though Vietnam heavily cracks down on critics, few anti-government organisations or activists have been jailed for terrorism, which is punishable by death in the authoritarian state.

Vietnam's police-run security ministry on Tuesday labelled the California-based Provisional National Government of Vietnam (PNGV) terrorists, just weeks after 15 of its members were convicted of planting petrol bombs in 2017 at Tan Son Nhat international airport, the country's busiest.

"The PNGV is a terrorist organisation," the Ministry of Public Security (MPS) said on its website, adding that anyone found promoting or colluding with the group would be "punished in accordance with Vietnamese law".

PNGV emerged in Vietnam from relative obscurity following the December 2017 trial uncovering the foiled airport attack, which the judge said had been funded from abroad.

The group, formed in 1991, says its stands for free and fair elections in Vietnam, which it labels a "dictatorship" on its website.

Some of its members include former officials from the US-backed southern regime who fled to the United States after the end of the Vietnam War, according to MPS.

Five PNGV members were arrested in 2015 Vietnam for allegedly trying to buy weapons to commit terrorist acts, it added.

PNGV did not immediately respond to a request for comment.

Scores of dissidents are behind bars in Vietnam, many serving sentences for "anti-state propaganda" or attempting to overthrow the government, though terrorism convictions are not common.

Most are in jail for speaking out against the communist government or pushing for peaceful reform, not political violence.

In 2016, Vietnam labelled the US-based Viet Tan anti-government group a "terrorist organisation" for "instigating violence", a charge the group rejects.

Agence France Presse - January 30, 2018

Vietnam lists U.S.-based vietnamese group as 'terrorist' organization

Vietnam listed a U.S.-based group still loyal to the now defunct state of South Vietnam as a terrorist organization on Tuesday, the Ministry of Public Security (MPS) said.

The California-based Provisional Government of Vietnam, led by U.S. citizen Dao Minh Quan, established groups inside Vietnam to "execute acts of terrorism and sabotage, and assassinate officials", the ministry said in a statement.

Quan was a "former lieutenant" of the U.S.-backed Republic of Vietnam, the statement said, referring to the now defunct state, also known as South Vietnam, which once ruled the southern half of the country until the Vietnam War ended in 1975.

Quan did not immediately respond to a request for comment. A U.S. Embassy spokesman in Hanoi said the organization is not designated as a terrorist group by the U.S. State Department.

Despite sweeping economic reform in Vietnam, and increasing openness toward social change, including gay, lesbian and transgender rights, the ruling Communist Party retains tight media censorship and does not tolerate criticism.

Earlier this month, Vietnam jailed four men for flying the flag of South Vietnam. The flag, a bright yellow rectangle with three thin horizontal stripes, is used by political activists in Vietnam who oppose the Communist-controlled government in Hanoi.

A video on a website the MPS said was operated by Quan's group showed a convoy of cars moving through a U.S. town, some of which were flying the flag of South Vietnam. The website describes Quan as the "Prime Minister" of the Provisional Government of Vietnam.

In late December, a Vietnamese court jailed 15 people for their part in an alleged April bomb plot by Quan's group at Tan Son Nhat airport, the transport hub which serves Ho Chi Minh City - formerly known as Saigon, the capital of South Vietnam.

Fifteen people acted on instructions from an overseas group which had used social media to spread propaganda and recruit its members, local media said, citing the court indictment.

Vietnam, one of the top 10 countries for Facebook users by numbers, has called for tougher internet controls and set up a military cyber unit to fight "wrong" views online.

The group "planted fuel bombs in the car park and at the arrival hall at Tan Son Nhat International Airport" in April, 2017," Tuesday's MPS statement said.

By James Pearson - Reuters - January 30, 2018