HANOI, April 17 - Police in Vietnam on Tuesday arrested a former senior police official and a former head of the central city of Da Nang, and placed four others under house arrest as the government widened a crackdown on corruption.

Phan Huu Tuan, former deputy head of the Ministry of Public Security's intelligence department, was detained on suspicion of revealing state secrets, the Ministry of Public Security said on its website. It did not elaborate.

Police also arrested Tran Van Minh, former chairman of the coastal city of Da Nang, on suspicion of violating state regulations on land management and state assets, it said.

Police also placed under house arrest another former chairman of the city, Van Huu Chien, along with three officials from the city's department of natural resource and environment and the city's investment promotion agency.

They are suspected of violating land management regulations, the ministry said.

Tran Van Minh, former chairman of Da Nang in the 2006-11 tenure. Photo: Tuoi Tre

Minh was the chairman of Da Nang from 2006 to 2011, while Chien was chairman from 2011 to 2014.

The city is a bustling tourism hub and the venue for the Asia Pacific Economic Cooperation summit attended by U.S. President Donald Trump and other world leaders.

The ministry statement said the arrests were part of a wider criminal case involving businessman Phan Van Anh Vu, who was arrested in January over allegations of revealing state secrets, tax evasion and abuse of power.

Neither Vu nor his legal representatives have commented publicly on the allegations against the 42-year-old entrepreneur.

Vietnam has in recent years stepped up its fight against corruption, with several senior government officials and executives of state-owned enterprises arrested and jailed..

Van Huu Chien, former chairman of Da Nang in the 2011-14 tenure. Photo: Tuoi Tre

Last month, a court in Hanoi jailed former Politburo member Dinh La Thang for 18 years for financial irregularities at a state-owned enterprise, adding to a 13-year sentence handed down separately in January. 

Thang, 57, who denied any wrongdoing at his trial, is the highest-level politician to have been sentenced in Vietnam for decades.