Santiago, Chile - The government of Chile's new right-wing president Jose Antonio Kast signed a memorandum with the US on Thursday to cooperate on the supply of critical minerals and rare earths.

Chile is the world's leading producer of copper and the second-largest producer of lithium, critical to the tech and green energy sectors.

China, which dominates the global supply chain for critical minerals, is Chile's top customer for both metals.

On his first full day in office, the US-backed Kast presided over the signing of a joint declaration between US Deputy Secretary of State Christopher Landau and Foreign Minister Francisco Perez Mackenna to "establish consultations" on the minerals.

The two countries committed to "explore financing mechanisms, both private and public, for investment projects involving critical minerals," the Chilean foreign ministry said in a statement.

"Mutual support in the supply of critical minerals is fundamental for the national security and commercial industries of both countries," the ministry added.

President Donald Trump has moved to aggressively reassert US dominance in Latin America in the face of competition from China for trade and influence.

Kast took office in the wake of a furore caused by a project to link Chile and Hong Kong via a submarine fiber optic cable.

Washington sanctioned three officials from former left-wing president Gabriel Boric's administration for green lighting the project, even after the government had rescinded its approval.

In the run-up to his inauguration, Kast accused Boric of withholding information about the project.