Vietnam’s recent political turmoil intensified on Friday as the head of its Parliament resigned, the latest high-level government departure amid a widening anticorruption campaign that has raised questions about the stability of the country.

Vuong Dinh Hue, the chairman of Vietnam’s National Assembly, submitted his resignation on Friday after the Central Inspection Committee found that he had violated regulations governing Communist Party members. It did not specify what these regulations were, but it came four days after his assistant was detained on charges of abuse of power.

“Mr. Vuong Dinh Hue’s violations and shortcomings, according to the Central Executive Committee, have caused bad public opinion and affected the reputation of the Party, the state and him personally,” the Vietnamese government wrote in a post on Facebook.

Mr. Hue was one of the “four pillars” of leadership in Vietnam — the others being the leader of the Communist Party, the prime minister and the president — which had made him a possible candidate for the future leadership of the party. His resignation is likely to add to anxiety among officials in Vietnam of an intensifying power struggle ahead of a coming leadership transition, in 2026, and to unnerve foreign investors who have flocked to the country in recent years.

Mr. Hue was the fourth Politburo member to have resigned or been fired from his position since 2021. Last month, the president, Vo Van Thuong, resigned after the Communist Party said he had violated its regulations. He was the second president to step down in a little over a year.

The question in Vietnam now is who would succeed Nguyen Phu Trong, the leader of the Communist Party. Mr. Trong, who was reappointed as general secretary for an unprecedented third five-year term in 2021, is 80 and thought to be in poor health.

In 2016, Mr. Trong launched the “blazing furnace” anticorruption campaign, saying graft could threaten the survival of the Communist Party. Thousands of party members across all levels of government have been sacked, dismissed from the party or imprisoned, though many have questioned whether some of these targets were political purges within a closed political system.

Mr. Hue appeared to be popular among his peers. In October 2023, during a vote of confidence for 44 members of the National Assembly, he received 91 percent of the total votes, the highest percentage in the group.

Earlier this month, Mr. Trong led a high-level Vietnamese delegation to China. He was last seen in public earlier Friday morning, when he visited the mausoleum of Ho Chi Minh, the former president and revolutionary hero, alongside the prime minister ahead of next week’s 49th anniversary of the end of the Vietnam War and the reunification of North and South Vietnam under communist rule.