The arrest of Ha, who is also the deputy chairman of the National Assembly Office, is part of a wider investigation into a bribery case at Thuan An Group, the ministry said in a statement.

The investigators are “focusing its forces on expanding the investigation, and clarifying the alleged violations of the accused and alleged violations at Thuan An Group and other related organisations,” the statement said.

The National Assembly Office did not immediately respond to Reuters’ request for comment.

Vietnam’s graft crackdown, dubbed “Blazing Furnace”, has seen hundreds of senior state officials and high-profile business executives prosecuted or forced to step down.

Last week, police said they had arrested six people on accusations of violations of bidding laws, including the chairman and the chief executive officer of Thuan An Group.

Thuan An, founded in 2004, specialises in infrastructure construction and real estate trading, according to the government.