Three local reporters accused of extortion were arrested by the Anti-Corruption Unit on Friday night as they enjoyed a party at a restaurant in Kampot.

It marks the first time that the ACU, usually seen as an organisation that targets government officials, has arrested journalists.

Im Chiva, deputy chief of Kampot province police, said details on the case were unclear.

“I do not know in detail whether they extorted money or who they extorted from because this case is being investigated by the ACU,” he said.

The journalists – Sor Sunly, a reporter for Hang Meas TV and Kampuchea Thmey, Tol Hok Ly, a reporter for TV 9, and a man known as Sovann who works for Apsara TV – have been sent to Phnom Penh for questioning.

Om Yentieng, head of the ACU, only briefly answered his phone to say he was busy questioning a suspect.

Meas Rithy, deputy director of Hang Meas TV, did not respond to calls but told a local newspaper he was surprised the ACU arrested one of the network’s reporters in Kampot, although he was not aware of any updates on the case.

“I support the ACU’s arrest of our reporter in Kampot if he committed anything illegal, which is against the journalism code,” he said.

On Tuesday last week, Om Yentieng said to reporters during a meeting between the ACU and the private sector that 700 to 800 corruption complaints had been filed to the ACU so far in 2014, an increase from previous years.

Yentieng said that the ACU was cracking down hard on corruption and had arrested “many people”, including eight judicial officials.

Preap Kol, head of Transparency International in Cambodia, said the journalists’ arrest was within the ACU’s rights, although arresting local TV reporters could be seen as avoiding going after bigger fish.

“Based on the Anti-Corruption Law the ACU can arrest anyone from any profession as long as the case involves corruption,” Kol said. “But people might wish to see the ACU focus more on big cases involving senior public officials.”

The ACU itself came under fire last week after Transparency International released a report about corruption in Cambodia which slammed the country’s judicial and law enforcement sectors and rated anti-corruption efforts as “weak,” receiving a low score of 34/100.

According to the report, the Kingdom’s anti-corruption bodies, referred to collectively as the Anti-Corruption Institution, or ACI, “requires considerable development in a number of areas”.

“The closeness of the ACI to the Prime Minister and ruling party curtails the ability of the ACI to function independently,” it adds.

The institution’s score in the sub-category of practical independence was zero.

Pa Ngoun Teang, executive director of the Cambodia Centre for Independent Media, said he had not yet heard of the case of the three journalists, but said that one of the major obstacles to media freedom in the country involved cases where “the courts are not independent”. However, corruption among journalists was not unheard of.

“There are some who are professional, but there are some involved in corruption [and] that is bad for Cambodia.”