Japan said it has taken a significant step in the controversial and complex race to mine the world’s ocean floors for valuable minerals.

Near the remote Japanese island of Minamitorishima, a team of scientists said in recent days that they had successfully pumped up mud from the seafloor, 6,000 meters beneath the waves, that is rich in rare earth elements.

Japan’s prime minister, Sanae Takaichi, hailed the government-led effort in a statement calling it a “world’s first.” She said it could pave the way for Japan to develop new sources for the valuable elements used in technologies like electric vehicles, smartphones and military equipment.

China currently dominates the global supply of rare earths, an economic vulnerability that Japan has long tried to remedy. It recently announced a partnership with the U.S. and the European Union after Beijing sparked global concern by throttling exports of rare earths of last year.

President Trump has made seabed mining a priority. The administration is speedily moving to issue commercial permits for companies to mine the ocean floor in international waters — a plan that has drawn sharp criticism from other countries. (Japan’s test, which runs for another week or so, is taking place in the country’s own territorial waters.)

Vast stretches of the ocean floor are rich in minerals but mining would be costly and technologically complex, and there is currently no commercial seabed mining. Researchers in Japan and various mining companies around the world have spent years developing systems capable of reaching such depths.