Chinese police arrested 137 people, among them doctors, suspected of trafficking human organs in a nationwide crime ring that profited from the huge demand for transplants, authorities said.

In a sting operation beginning in late July, police pounced across 18 provinces and regions and "rescued" 127 people who had agreed to donate organs to illicit traders, the Ministry of Public Security said.

Eighteen doctors were among those detained, suspected of performing illegal transplant operations, the ministry said in a report posted on its website late Saturday.

"The suspects usually used forged identities to recruit healthy candidates from the Internet and put them under secret confinement separated from the outside world," it said.

"The suspects sought patients in need of organ transplants from hospitals or the Internet and matched them with healthy donors."

The crackdown on traffickers comes after state media reported in April that a teenage high-school student sold a kidney for an illicit transplant operation and used the proceeds to buy an iPhone and iPad.

The 17-year-old boy, who was paid 22,000 yuan ($3,500), was recruited from an online chatroom. The Xinhua news agency said at the time the boy was suffering from kidney failure and in deteriorating health.

More than 1.5 million Chinese need organ transplants, but only about 10,000 such operations are performed in the nation annually, Xinhua said, citing statistics from the health ministry.

The huge demand has led to a thriving illegal market for organs, the ministry said.

Executed prisoners remain the main source of organs used in transplant operations due to the lack of voluntary donations, Vice Health Minister Huang Jiefu was quoted by state media as saying early this year.

Following repeated criticism from overseas rights groups, Huang pledged to wean the nation off of its dependency on organs from prisoners.

International human rights groups have long accused China of harvesting organs from executed prisoners without the consent of the prisoner or their family -- charges the government has denied.

The lack of available organs for transplants largely stems from an absence of a "transplant culture" in China compared to the West and the traditional idea that the body must be left as it is at death.