Two independent journalists were detained by local authorities after they published a report alleging corruption by a local official in southwestern China, rights group Reporters Without Borders (RSF) said on Tuesday, condemning the incident.

Police in Chengdu said they were investigating a 50-year-old man surnamed Liu and a 34-year-old surnamed Wu on suspicion of making "false accusations" and conducting "illegal business operations."

Authorities said they were placed under "criminal coercive measures," a term typically referring to detention.

Chinese media and RSF identified the two journalists as Liu Hu and Wu Yingjiao.

The detentions followed publication of an online report examining alleged corruption involving Pu Fayou, Pujiang county Communist Party secretary in Sichuan, and other county officials.

The article has since been removed from the social media platform WeChat.

'China treats independent journalists as a threat'

RSF, the Paris-based advocacy group, said the case underscored an increasingly hostile environment for independent reporting in China.

"Anyone who dares to investigate malpractice by the Chinese regime is swiftly persecuted by the authorities," RSF's Taipei-based advocacy manager Aleksandra Bielakowska said in a statement to news agency AFP.

China ranks 178th out of 180 countries in RSF's press freedom index and is the world's "biggest jailer of journalists," the group said.

"Under [Chinese President] Xi Jinping's leadership, control over information has tightened to near-totalitarian levels, with independent journalists treated as a threat to the state", Bielakowska said.

Liu, an investigative journalist, was previously arrested in 2013 for alleged defamation, but later released on bail after spending 364 days in detention, according to RSF.

Edited by: Elizabeth Schumacher