Tran Cong Khai, 56, received the jail sentence for the charge of "carrying out activities aimed at overthrowing the people’s administration" at a trial in Ho Chi Minh City on Thursday.

Khai, who used to work as a lawyer, was a member of the "Provisional National Government of Vietnam," an organization founded by Vietnamese American Dao Minh Quan in the U.S., which aims to overthrow the Vietnamese government through violence and acts of terrorism, the indictment said.

It said Khai had joined other members to build plans to sabotage the Asia Pacific Economic Cooperation (APEC) Summit that Vietnam hosted in the central city of Da Nang in 2017. The event gathered leaders from 21 economies, including President Xi Jin-ping of China and President Donald Trump of the U.S.

Khai and other members were assigned to release balloons attached with the organization’s motto, and leaflets in the areas where conferences were held. They were arrested before they could execute the plan.

According to investigators, Khai’s accomplices had limited knowledge and that they had limited education, lack of legal knowledge and had cooperated during the investigation and therefore, they were not prosecuted.

According to the indictment, the "Provisional National Government of Vietnam" was established in 1990. Since late 2013, its members have propagandized to distort guidelines and policies of the Vietnam government and its Communist Party. Together, they enticed people to provoke terrorism, spread leaflets calling for protesting and sabotaging national holidays in Vietnam, it said.

In March 2017, Khai was invited to join the organization. One month later, he made referenda for others to vote Dao Minh Quan as "president of the Republic of Vietnam."

The Ministry of Public Security in January last year classified the organization as terrorist. Vietnamese authorities have already issued international arrest warrants against Quan and six other members, all of whom are living in the U.S. or Canada.

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

The organization was 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 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.