The Communist party boss, Nguyen Phu Trong, has brushed aside complaints from Germany and ordered the trial of a fugitive allegedly abducted from Berlin.
Germany has been demanding the return of the former state oil company executive, Trinh Xuan Thanh, who was bundled into a car by suspected Vietnamese agents in July and spirited back to Hanoi. He had been on the point of claiming asylum in Germany on the grounds that he was being persecuted in Vietnam for political reasons.
Mr Trong, who also chairs the party’s anti-corruption body, urged prosecutors to proceed with Mr Thanh’s trial for embezzlement by February next year at the latest.
He has staked much personal prestige and authority in hunting down the former state oil company executive, even at the expense of poisoning relations with Germany, an important trading partner.
Mr Trong had told constituents in April that he would use “all means” to track down Mr Thanh, who had fled the country after being accused of presiding over massive losses while at the construction arm of PetroVietnam.
The party general-secretary is sending a signal to potential rivals that he is deadly serious about what he calls his anti-corruption campaign, and will not allow diplomatic considerations to interfere with his domestic priorities.
The party leadership has taken a similar approach to foreign protests over a parallel crackdown on independent bloggers and other government critics.
Mr Thanh is accused of violating state regulations on economic management, leading to the loss of the equivalent of $147 million while he was director of PetroVietnam Construction between 2007 and 2013.
The anti-corruption campaign has targeted a number of officials associated with the state oil firm at a time when Mr Trong’s main rival, the former prime minister, Nguyen Tan Dung, held sway over economic policy.
Mr Thanh appeared on state television in early August saying that he had turned himself in after thinking twice about his decision to flee the country.
Germany said it had evidence that he was abducted by armed Vietnamese agents from a park in central Berlin. It has since expelled two Vietnamese diplomats, frozen out contacts with the embassy in Berlin and suspended a range of economic contacts between officials.
Germany has warned of possible further measures against Vietnam should it continue to ignore the request for a full explanation.