North Korea has proposed allowing China to mine rare earths in the country in return for building solar power plants there, a Chinese industry group said Thursday.

But it is uncertain whether China will accept the proposal by North Korea, which has chronically faced power shortages, given that the U.N. Security Council has imposed economic sanctions aimed at thwarting the nation's nuclear and ballistic missile ambitions.

Chinese Foreign Ministry spokeswoman Hua Chunying told reporters on the same day that the country's government "has not heard at all" about such negotiations.

On its website, the Association of China Rare Earth Industry quoted a person familiar with the matter as saying that China's investment in solar power plants in Pyongyang or other areas in North Korea could cost around $2.5 billion.

China is the world's dominant supplier of rare earths, which are vital in the production of high-tech goods such as hybrid cars and mobile phones.

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