A former top police official in Vietnam was arrested Friday on suspicion of involvement in a multimillion-dollar international gambling ring, part of the ruling Communist Party's crackdown on corruption.

The Ministry of Public Security said on its website the arrest warrant was issued for Phan Van Vinh for abuse of power while doing official duty as part of an investigation into gambling and money laundering.

Vinh, 62, was the head of the General Department of Police Force before retiring last year. The president stripped Vinh's "people's police" title earlier Friday.

Last month, police arrested Nguyen Thanh Hoa, former head of a national police department tasked with fighting high-tech crimes, for allegedly organizing gambling in the case.

The ministry said earlier that 31 people have been arrested in the case so far and police have seized cash and other assets worth $54 million.

The ring had operated from April 2015 until it was broken up in August last year with some $670 million having been gambled online, the ministry said, adding that three ring leaders made $152 million in illegal profits.

Vietnam's unprecedented crackdown on graft previously focused on corruption at the state energy giant PetroVietnam and the banking sector but appears to be spreading to the police force.

Scores of PetroVietnam senior officials and bankers have been brought to trial, the most high-ranking of them being Dinh La Thang, a former Politburo member who was sentenced to 13 years in prison in January and another 18-year jail term last month for mismanagement in two separate cases dating to his time leading PetroVietnam.

He was the first Politburo member to be jailed in decades.