China will investigate whether 17 Japanese tourists received illegal organ transplants, state media said Tuesday.

The China Daily newspaper reported that the Japanese patients apparently were operated on after China banned the trade in human organs in May 2007.

China will punish the doctors and medical institutions responsible, Deputy Minister of Health Huang Jiefu said, the newspaper reported.

China has the second-highest number of transplants after the United States, with 5,000 operations performed every year, the newspaper said. But it does not allow transplants for foreigners because there is a severe shortage of organs for its own citizens.

More than 1 million Chinese need transplants every year, but there are only about 10,000 donors, China Daily reported.

The underground organ trade in China has been a notorious supplier of organs to foreigners desperately in need of transplants, who make up as much as 40 percent of the market. Brokers regularly arrange transplants in weeks rather than the months or years it generally takes in the West.

It is not clear how the Japanese received the transplants. A press officer at the Japanese Embassy said they did not have any information about the transplants.

Only 160 medical institutions in China are licensed to perform transplants, and then only with approval from provincial health departments, according to the official Xinhua News Agency.

Huang said China plans to develop a national registration system regulating organ transplants at all facilities.

China has been making efforts to better regulate organ transplants. In late 2007, medical officials agreed not to transplant organs from prisoners or others in custody, except into members of their immediate families.

China previously had acknowledged that kidneys, livers, corneas and other organs are routinely removed from prisoners sentenced to death row, but only when consent is provided.

Earlier in 2007, China's State Council, or Cabinet, issued regulations making it illegal to harvest human organs without permission. The rules also included a ban on the sale of human organs for profit and on donations by people under 18.

Voluntary donations remain far below demand in China, partly due to cultural biases against organ removal before burial.