The agreement connects CATL, the world's largest manufacturer of electric vehicle batteries, with Bolivia's salt flats that are home to the world's largest lithium resources.

Following a meeting with CATL executives on Sunday, Bolivian President Luis Arce confirmed the commitment to build two lithium plants to extract minerals from the country's Uyuni and Oruro salt flats.

"We met with Burton Roy (Yu Bo), CEO of the Investment Committee of CATL to confirm the investment of $1.4 billion," the president said via Twitter, adding that as partners they would "evaluate the possibility" of increasing investments to 2028.

Construction of both plants could begin as soon as July, according to the country's energy ministry, with overall investment climbing to around $9.9 billion during the project's industrial process.

Sunday's announcement follows a partnership deal signed on January 20 between Bolivia's state-run lithium company, Yacimientos del Litio Bolivianos (YLB), and a Chinese consortium, in which CATL would invest over $1 billion in the project's first stage in exchange for rights to develop the two lithium plants, which could each produce up to 25,000 metric tons of battery-grade lithium carbonate per year.

CATL does not currently produce any lithium, although it has invested in a number of Chinese projects.

Lithium resources in Bolivia's iconic salt flats are estimated at 21 million metric tons, according to the U.S. Geological Survey, but as yet has almost no industrial production or commercially viable reserves.

(Reporting by Daniel Ramos and Lucinda Elliott; Editing by Chizu Nomiyama)