China on Wednesday reiterated that all sides should continue to uphold and implement the Iran nuclear deal.

Foreign Ministry spokeswoman Hua Chunying made the remarks at a daily news conference after Israeli Prime Minister Benjamin Netanyahu unveiled files about Iran's "secret nuclear archive" that made the prospect of the agreement more gloomy.

The disclosure by Netanyahu on Monday came ahead of United States President Donald Trump's looming deadline on May 12 to decide whether to extend the waiver on nuclear-related sanctions against Iran, according to Xinhua.

Hua noted that China has noted such reports and reactions made by relevant sides.

The Joint Comprehensive Plan of Action reached by Iran and China, France, Russia, the United Kingdom, the US and Germany in 2015 is to ensure that the country's nuclear plan is for a peaceful purpose, Hua said.

The International Atomic Energy Agency is the only international organization with the authority to supervise the deal and draw conclusions on the nature of Iran's nuclear plan, Hua said, adding that it has confirmed 10 consecutive times that Iran has fulfilled its obligations.

"It is urgent for all parties to continue upholding and implementing the deal from an overall and long-term perspective," she said.