Former Politburo member Dinh La Thang was found guilty of economic mismanagement over losses in state oil firm PetroVietnam.

The trial is part of a showcase crackdown on corruption involving high-profile energy and banking executives.

Another executive from the firm, Trinh Xuan Thanh, was sentenced to life.

His case came to international attention last year, when the German foreign ministry accused Vietnam of illegally kidnapping him from Berlin, where he was seeking asylum.

The trial is seen by some as a showcase of the Communist Party's fight against corruption.

But correspondents say it is also seen by some as a purge of opponents of leading Party officials.

Twenty other people were sentenced on Monday at the trial in Hanoi, which was closed to foreign media.

They received jail terms ranging from three years suspended to nine years.

Trial of untouchable figures

Ever since a conservative faction of the Communist Party gained control of the politburo at the last party congress two years ago, it has pursued officials thought to have become unusually wealthy during the decade-long tenure of ousted Prime Minister Nguyen Tan Dung.

The Vietnamese people have since been offered the spectacle of once untouchable figures weeping and pleading for leniency.

The Party leadership is using the widely publicised trials both to break up any potential opposition by those close to Mr Dung, and to show the public that they are serious about curbing the corruption which has proliferated during Vietnam's rapid economic expansion.

Thang, who had been considered a rising star of Vietnamese politics, was sacked from the Politburo in May, a very rare move in the one-party state.

Since Vietnam started economic reforms in 1986, only two other Politburo members have been dismissed.

He was accused of "serious violations" in his leadership which had "hurt the Party's reputation".

In a tearful apology last week, he had asked forgiveness from the court.

Trinh Xuan Thanh was found guilty of embezzlement, for which he was sentenced to life, and of "deliberately violating state regulations on economic management, causing severe consequences", for which he received 14 years.

His case came to international attention last year, when Germany said he was allegedly bundled into a car by armed men at Berlin Zoo, and expelled Vietnam's press attache in protest.

Thanh later said he had returned to Vietnam voluntarily, but his lawyer said the confession had been forced.

On Wednesday, he will face a second trial on charges of embezzling public funds, which could see him given the death sentence.

In September last year, a former chairman of PetroVietnam, Nguyen Xuan Son, was sentenced to death for his role in the corruption scandal.

By Jonathan Head, BBC News - January 22, 2018