China's top quality watchdog said Friday that alarmingly high levels of radiation had been detected on two Japanese Wednesday upon their arrival in east China's Wuxi City from Tokyo.

The announcement was made shortly after the regulator said earlier Friday that the local quality control bureau had found "abnormal" levels of radiation on a Japanese merchant vessel that berthed in east China's Xiamen port, Fujian Province, on Monday.

The General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ) said the radiation was discovered on the two Japanese nationals when the local quality control bureau conducted radiation checks on passengers aboard flight ZH9056 that reached Wuxi, east China's Jiangsu Province, from Tokyo on Wednesday.

The AQSIQ said radiation on the two travelers was alarmingly high, and the case reported to the local environmental and health departments.

The AQSIQ said one of the two Japanese nationals came from Nagano Prefecture, about 350 km from the Fukushima Prefecture, and the other from Saitama Prefecture, about 200 km from Fukushima, where the radiation leaking Dai-Ichi nuclear power plant is located.

On Wednesday night, the two Japanese were sent to the Second Affiliated Hospital of Soochow University in Suzhou City for medical treatment. Their luggage and clothes were also detoxified, the AQSIQ said.

An AQSIQ official, who spoke anonymously, said the two Japanese tourists had not caused harm to others.

Earlier Friday, the AQSIQ announced abnormal radiation was found on a Japanese merchant vessel that berthed in Xiamen port, east China's Fujian Province, on Monday.

The vessel belongs to Mitsui O.S.K. Lines, a Japanese company with bulk transport services around the world.

The vessel is still docked at the port, and the local quality control authority is working with other government departments to "take more measures" on the matter, said an AQSIQ spokesperson without elaborating.

The spokesperson didn't say if high levels of radiation had been found on the ship itself or the goods onboard, but said more details would be provided by the local government.

The vessel had set off from the U.S. and reached Tokyo of Japan on March 17. On the same day, it left Tokyo and reached Xiamen port Monday night.

The AQSIQ on Monday asked the local quality control authority to monitor food imported from Japan for radiation following the nuclear disaster at its Fukushima Dai-Ichi power plant.

The AQSIQ has also ordered local quality watchdogs to test food from Japan for radiation to ensure the safety of China's food imports.

China's National Nuclear Emergency Coordination Committee announced Thursday that China would remain unaffected by radiation emitted from the quake-hit nuclear power plant over the next three days.

It said in a statement that currently, the radiation leaks from the plant would not have any impact on China's environment or the Chinese people's health.