The presidents of France and Brazil on Wednesday launched a submarine built in the South American country with French technology in a program that aims to build Brazil's first nuclear-powered submarine by the end of the decade.

Presidents Emmanuel Macron and Luiz Inacio Lula da Silva attended a ceremony in the Itaguai shipyard near Rio de Janeiro launching the third diesel-powered submarine built in a $10 billion partnership.

Brazil's first lady Janja da Silva smashed a champagne bottle on the bow of the submarine Tonelero and the two presidents activated a lever sending the Scorpene-class vessel into the sea.

The submarine program, begun in 2008 during Lula's previous presidential term, is a partnership with France's state-run Naval Group in which defense contractor Thales has a 35% stake.

The program, called ProSub, is Brazil's biggest international cooperation project in the defense sector, Lula said, and aims to protect its sovereignty over waters from where 85% of the country's oil and 75% of its gas comes.

The Brazilian government said its submarine fleet is needed to defend the country's nearly 7,500-kilometer (4,700-mile) coastline and the Atlantic waters where Brazil is developing vast offshore oil fields.

Macron is on a three-day visit to Brazil that aims to relaunch the bilateral relationship and strategic partnership that stalled during the previous government of Jair Bolsonaro, whom the French president criticized for failing to defend the Amazon rainforest.

Macron landed on Tuesday in the Amazon city of Belem, where Brazil will host the United Nations COP30 climate negotiations in 2025. Lula met him there and they pledged to work together to stop deforestation in the Amazon by 2030.

Macron will meet business executives in Sao Paulo later on Wednesday and make a state visit to Brasilia on Thursday.