The shortage of rare earth metals from China could harm the US and the EU, they both warned. (photo, from bbcimg.co.uk)
In Washington and Berlin, officials and industrialists said a lack of the minerals would have severe repercussions.
And 90% of the minerals come from China.
Many hi-tech products require the metals, and some are used by the US weapons industry.
China said that in order to protect the environment and preserve its own supply, it is cutting production.
The country denied using its near-monopoly improperly and said there will not be drastic cuts in exports.
There are 17 different rare earths metals, they are scarce minerals that have particular properties, like being magnetic or shining in low light. It makes them particularly useful in some new technologies, such as solar panels or electric cars or light-weight batteries.
German companies have lobbied the government to say that they are now finding it hard to get hold of these essential minerals, because China produces virtually all of them.
Germany is severely affected, said the country’s economy minister Rainer Bruederle.
And Washington is now echoing the concerns about a monopoly. The US Department of Energy has said firms are worried about shortages. One talked of a “supply crunch”.
Although efforts are being made in the US to increase production, this cannot be done in the near future.