More than 350 HIV/AIDS patients from across China have received scam calls as of Monday evening and said their personal information has been leaked, according to a major AIDS support group in China.

The patients come from all 31 provinces, autonomous regions and municipalities in China, and they have shared their experiences with BHL China League, an online interactive platform for HIV/AIDS patients based in Beijing, according to Bai Hua, chief of the league.

"The actual number of patients affected by the privacy leak and getting scam calls may be much higher than what we have received," he said.

In the scam, HIV/AIDS patients have received calls from someone who says they are from local health authorities and asks them to transfer money so the patients will get certain subsidies in the future, Bai said.

As of Monday, four patients said they were cheated out of money, including one in Beijing who lost 6,700 yuan ($1,000), he said.

The callers have detailed personal information about the patients, including their names, ID number and dates of confirmation that they have HIV/AIDS, Bai said. Patients started to share the scam call experience about 10 days ago on social media platforms of the league, but the number of patients involved has surged since Friday, he said.

The Chinese Center for Disease Control and Prevention said on Monday that it has reported the case to police and has notified local CDCs and urged them to alert HIV/AIDS patients of the scam.

After finding out about the scam calls, the center immediately conducted a safety inspection of its information system involving HIV/AIDS patients and took measures to better secure the system, it said.

No organization or individual is allowed to make public the personal information of HIV/AIDS patients or their families, such as their names, address, employers or medical records, unless they are given the consent of the patients or their guardians, according to a regulation on the control and prevention of AIDS adopted by the State Council.

According to a joint statement released on Monday by the World Health Organization and the Joint United Nations Programme on HIV/AIDS, "The leak of personal information of people infected with HIV is a violation of the fundamental right to patient confidentiality."

"WHO and UNAIDS welcome the Chinese health authorities' swift response to this incident－including the investigations currently underway into the alleged fraudulent activity, as well as the information security breach which enabled information about people living with HIV to be accessed by people without authority to do so," the statement said.

Bai said: "Many HIV/AIDS patients are now in a state of anxiety, and they have no idea how their information, which is assumed confidential, was leaked. They are worried about whether they will be blackmailed in the future."

It is possible that the database of China CDC has been hacked, or that the information was leaked by CDC employees, Bai said.

Ruan Chuansheng, a criminal lawyer in Shanghai, said the maximum penalty for illegally leaking personal information in China is seven years in prison plus fines.

Cao Yin contributed to this story.