A French energy company says it has deliberately released gas from a Chinese nuclear power plant in a bid to fix an "issue".
EDF confirmed that there was a build-up of noble gasses in one of the two reactors' primary circuits.
It comes after CNN reported that the US government had been assessing reports of a leak at the Taishan plant.
The plant's Chinese part-owner, China Guangdong Nuclear Power Group, refuted claims of a leak on Monday.
A spokesperson for EDF said that the coating on some of the fuel rods had deteriorated.
The gases were collected and treated before being released into the atmosphere in "accordance with regulations".
CNN reported that Framatome, owned by EDF, had sent a letter to the US Department of Energy, warning them of the potential leak. It also warned that the Chinese safety authority was raising the acceptable limits for radiation detection outside the plant to prevent it from being shut down.
Sources told CNN that the Biden administration had discussed the situation with the Department of Energy's experts and the French government. However the facility was not believed to be at a "crisis level" yet.
EDF also announced on Monday that it had called a meeting of the plant's board.
China Guangdong Nuclear Power Group told state outlet the Global Times that the nuclear plant has operated the reactors strictly in compliance with business licence documents and technical procedures.
All the two reactors' operation indicators have been in line with nuclear safety regulations and the technical requirements of electricity plants, the company said.
The International Atomic Energy Agency told the Associated Press that it was aware of the reports and it was in contact with its counterpart in China.
The plant provides power for the Guangzhou and Shenzhen areas, both major manufacturing hubs. The area has faced power shortages in recent weeks due to hot weather and lower than normal hydropower supplies from Yunnan province.