Medical workers in east China's Zhejiang Province have handed in 18 million yuan (about 2.8 million U.S. dollars) in bribes they received from pharmaceutical companies this year, local health authorities said Friday.

The money was voluntarily remitted into bank accounts that were set up by medical institutions at all levels, said Cai Xinguang, a discipline inspection official from the provincial health department.

Provincial health authorities kicked off an anti-bribery campaign in all of the province's hospitals at the beginning of this year.

The campaign was launched after a number of medical industry bribery cases were exposed on the Internet, which aroused widespread public outrage.

Over the last 6 months, 170,000 doctors, nurses and other medical staff in more than 1,200 hospitals in Zhejiang have pledged to refuse bribes, Cai said.

Provincial health authorities, working together with police, have intensified their efforts to crack down on cases of medical industry bribery, Cai said, adding that the anti-bribery campaign will continue.

Earlier this month, an Internet post revealed that more than 110 doctors in two hospitals in Zhejiang's city of Wenzhou accepted kickbacks from a pharmaceutical company after purchasing one of the company's products.