Truong Duong, 40, was found guilty of engaging "terrorism to oppose the people's administration." Two of his accomplices, Pham Anh Dao (also known as Lisa Pham), 39, and Ha Xuan Nghiem, 57, are on the run.

Duong, a driver for a foreign company in Thu Dau Mot Town of the southern province, worked with a terrorist organization called the "Provisional National Government of Vietnam," the indictment said.

Last August, he was asked by Pham, a member of the organization, to plant an explosive at the Binh Duong tax office. Pham instructed Duong to go to a convenience store in town and receive a package delivered by Nghiem. Four bombs made with around 1.2 kg of gunpowder were in the package.

On September 30, Duong took the explosives inside an urinal on the tax office's first floor. An explosion followed 20 minutes later, collapsing walls and shattering glass in the building. There was no casualty.

Duong was arrested four days later. He admitted his crime to the court and asked for his sentence to be reduced. Besides his prison sentence, Duong was ordered to compensate the Binh Duong Tax office with VND800 million ($34,000) for damage caused.

The "Provisional National Government of Vietnam" was established in 1990 in the U.S. Its aim is to overthrow the Vietnamese government through violence and acts of terrorism, according to the Ministry of Public Security. The organization is headed by Dao Minh Quan, who has proclaimed himself the "prime minister" of this "government." The public security ministry declared it a terrorist organization in 2018.

Vietnam has already issued international arrest warrants against Quan and six other members, all of whom are living either in the U.S. or Canada.

In August 2018, two of its members, both Vietnamese-Americans, were jailed for making plans to sabotage the country's celebration of the Reunification Day on April 30.

The organization is also accused of being behind a petrol bomb attack that burnt 320 motorbikes at a police warehouse in the southern Dong Nai Province in April 2017; and a failed terror attack at HCMC's Tan Son Nhat International Airport later that month.

A HCMC court in December 2017 sentenced 15 Vietnamese to between five and 16 years in prison for the two attacks.