French President Emmanuel Macron and Brazil’s President Luis Inacio Lula da Silva celebrated the launch of Brazil’s third French-designed submarine at Brazil’s naval base in the Itaguai shipyard near Rio de Janeiro on Wednesday.

The submarine is part of the countries’ defense partnership and serves to help secure Brazil’s 8,500-kilometer-long coastline, dubbed the “Blue Amazon,” where 85% of the country’s oil, and 75% of its gas is transported. This sub is the third of four planned diesel attack submarines built in a $10 billion partnership with training, equipment and technical assistance from France.

This is a realization of a submarine program called ProSub, outlined in 2008 between Lula during his first presidential term and then-French President Nicolas Sarkozy. The fourth submarine is set to launch in 2025.

According to Lula, France and Brazil’s defense ties “will allow two important countries, each on a continent, to prepare so that we can face this adversity, without worrying about any type of war, because we are defenders of peace.”

Macron noted that, despite their differences, “the great peaceful powers of Brazil and France” had “the same vision of the world” in addition to their economic alliance.

Macron is currently on a three-day tour of Brazil in order to raise over a billion dollars for green investments to protect the Brazilian and Guyanese Amazon rainforest and help amend diplomatic ties that were strained under former Brazilian President Jair Bolsonaro. His visit marks the first by a French president in over a decade.

Lula said during a speech that Macron’s visit is part of a global effort to beef up rainforest protections.

“We want to convince those who have already deforested that they need to contribute in an important way to countries that still have their forests to keep them standing,” Lula said.

The two presidents were photographed laughing and holding hands in the jungle, prompting internet memes about their burgeoning “bromance.” This was a far divergence from previous incidents when Bolsonaro lobbed insults at Macron’s wife.

In addition to the diesel submarines, Brazil is also planning to build its first nuclear-powered submarine. However, it has experienced significant delays, mostly due to budget constraints and hesitations from its French collaborators about nuclear proliferation.

“If Brazil wants to have access to knowledge of nuclear technology, it is not to wage war. We want this knowledge to assure all countries that want peace that Brazil will be at their side,” Lula said.

Macron told Brazil “France will be at your side” during the development of the nuclear-powered submarines, without announcing specific assistance.

“I want us to open the chapter for new submarines … that we look nuclear propulsion in the face while being perfectly respectful of all nonproliferation commitments,” he said.

Some information for this report was provided by The Associated Press, Reuters, and Agence France-Presse.