Ngo Hao, 65, who served under the US-backed regime in South Vietnam during the Vietnam War, was convicted at a trial in south central coastal Phu Yen province Wednesday, the official told AFP.

He was accused of activities seeking a multi-party political system under the instruction of the Bloc 8406 pro-democracy movement, which is banned in Vietnam, media reports said.

According to the Vietnam News daily, Hao also "wrote articles and distributed documents that contained distorted information about the regime and defamed leaders" between 2008 and 2012.

He was arrested in February this year.

At least 47 activists have been convicted on anti-state charges in communist Vietnam this year.

In February, a court in the same province of Phu Yen sentenced 22 activists to jail terms ranging from 10 years to life imprisonment in one of the country's largest subversion trials for years.

The harsh punishments are part of an escalating crackdown by the communist regime on dissent, triggering growing international concern.

Agence France Presse - September 12, 2013