China, with whom Trump has threatened a trade war, is the world's largest producer of rare earths and many other critical minerals. Trump has also expressed interest in making Greenland, an autonomous territory of Denmark which also sits on large rare earth deposits, a part of the U.S. since his reelection.

The president appears to have adopted a proposal first made last year that offers “strategic partners” such as the U.S. special access to Ukraine's glut of natural resources.

The U.S. president’s transactional approach builds on a suggestion Kyiv set out in its “Victory Plan” aimed at retaining U.S. support.