Vietnam's President Vo Van Thuong has resigned after just one year in the job, the ruling Communist Party announced Wednesday, as the country mounts a sweeping anti-graft purge.

The party said Thuong was guilty of "violations and shortcomings" and his resignation was accepted by the central committee.

The 53-year-old's dramatic fall comes as Vietnam undergoes major political upheaval, with his predecessor forced out in an anti-corruption drive that has seen several ministers fired and top business leaders tried for fraud and corruption.

A statement on the party's website said Thuong had violated unspecified "regulations" and failed to set a proper example as head of state.

"Comrade Vo Van Thuong's violations and shortcomings have caused bad public opinion, affecting the reputation of the Party, State and himself personally," said the statement, initially reported by the state Vietnam News Agency.

"Fully aware of his responsibility to the Party, State and People, he submitted his resignation from his assigned positions."

The rubber-stamp National Assembly will hold an extraordinary session on Thursday to confirm the resignation. 

Graft purge

Thuong became president on 2 March last year after president Nguyen Xuan Phuc resigned in a sudden move unusual for Vietnam, where political changes have long been carefully orchestrated, with an emphasis on stability.

Before Phuc, only one other Communist Party president had ever stepped down, and that was for health reasons.

When he took office, Thuong said he was "determined to fight corruption", and he was believed to be close to party General Secretary Nguyen Phu Trong -- who is seen as the most powerful figure in the country.

Detailed reasons for Thuong's departure have not been made public.

But the Ministry of Public Security this month announced it was expanding a probe into an infrastructure development company in three provinces, including central Quang Ngai, where Thuong was formerly the party chief.

The ministry said the Phuc Son company was suspected of falsifying financial statements in order to dodge taxes, and its investigators arrested nine people including five officials from Quang Ngai.

But analyst Benoit de Treglode of the Institute of Strategic Research in Paris said machinations within the Communist Party were likely behind the move.

"This departure is part of clan rivalries within the party before a renewal of the elites, given that Trong's health is deteriorating," he told AFP.

"It's not just another case of corruption, it's the beginning of manoeuvres to designate the new leader of Vietnam." 

When Phuc quit in January last year, state media said the party had found him responsible for wrongdoing by senior ministers under him during his 2016-2021 stint as prime minister, before he became president.

Two deputy prime ministers were sacked around the same time along with dozens of officials, many because of graft allegations linked to deals done as part of Vietnam's Covid-19 pandemic response.

Party chief Trong is regarded as the architect behind the anti-corruption drive, which has proved popular among the Vietnamese public.

Two major fraud and corruption trials got underway this month involving some of the country's top business leaders.