Hillary Clinton, US secretary of state, has called for the US and its partners to reduce their dependence on China's production of so-called rare earths, in some of the most forthright comments on the topic by a senior American official.

But she welcomed a statement by Beijing on Thursday that it would not use its sway over the market as a bargaining tool with other economies.

Beijing dominates the market with some 97 per cent of production, even though it has only 36 per cent of world reserves.

China made that announcement after Mrs. Clinton decided to visit the country on her prolonged Asian tour.

The Obama administration has also been looking into reports that China had halted some shipments to the US.

She is due to meet Dai Bingguo, state counselor for foreign policy, in Hainan Island on Saturday.

This year it has cut export quotas, increased duties and has been accused by Tokyo of choking off Japan's supplies-an accusation China has denied.

Rare earths are used for high-technology products such as precision-guided weapons and hybrid cars.

"These are elements that are critical to industrial production, not only in Japan and the US."

"The entire world has to seek additional supplies in order to protect the important production needs that these materials serve," Mrs. Clinton said at a meeting in Hawaii with Seiji Maehara, Japan's foreign minister.

Her comments come at a time of strain in US-Chinese ties over issues such as Beijing's renminbi policy, its subsidies for green energy, and US efforts to deepen co-operation with many of China's neighbors in south-east Asia.

being so dependent on only one source, risked disruption through natural disasters or "other kinds of events".

Mrs. Clinton added that the current focus on rare earths "served as a wake-up call" that,