Nine presidents or vice presidents of 13 hospitals at the city- or district-level have been investigated for graft in Shenzhen, south China's Guangdong province.

Seven other department directors in these hospitals were also investigated after the anti-corruption department under Shenzhen's procuratorate initiated a campaign to crack down on commercial bribery in the city's medical system, said a press release issued by the procuratorate late Friday.

The campaign, launched at the beginning of this year, was aimed at graft activities involving top management officials in hospitals during equipment, drug and consumable purchases, said the release.

As the cases are still under investigation, the procuratorate did not disclose the details.

The city's health committee said it would cooperate with the procuratorate on the cases and launch a three-month campaign to further curb corruption in drug sales and health services.