(Recasts, adds details on funding, comment from paragraph 2 onwards)

Sept 24 (Reuters) - The United States has backed an Australian lithium and a rare earths project with up to $786 million in debt funding as Western countries seek to build supply chains for critical minerals.

Australia's American Rare Earths said on Tuesday it had received a letter of interest for a debt funding package of up to $456 million from the Export-Import Bank of the United States (EXIM) to support construction of the Cowboy State Mine area at its Halleck Creek Project in Wyoming.

"We are hopeful that it will serve as an anchor to help attract private funding into the project," said Melissa Sanderson, a member of the company's board of directors.

The bank has also offered $330 million to finance the construction of Anson Resources' lithium production plant in the Paradox Basin, Utah, the Australian company said on Tuesday.

Earlier this year, the bank backed two Australia-listed listed rare earths projects by Australian Strategic Materials

and Meteoric Resources with up to $850 million of funding.

The United States and Australia established a critical minerals taskforce last year as Australia seeks to attract investment in minerals processing from allied countries, aiming to reduce reliance on China, which currently controls more than 80% of the global supply.

(Reporting by Roshan Thomas in Bengaluru; Editing by Mohammed Safi Shamsi and Subhranshu Sahu)

((Roshan.Thomas@thomsonreuters.com;))