President Joe Biden and Chinese President Xi Jinping addressed on Saturday what has been considered a long-term strategic risk. They agreed that any decision to use nuclear weapons should be controlled by humans, rather than by artificial intelligence.

The two leaders met at Xi’s hotel near the end of the 21-nation Asia-Pacific Economic Cooperation (APEC) summit in Lima, Peru. It was the third and final in-person meeting of Biden’s presidency. 

Biden's national security adviser Jake Sullivan said the agreement, which marked the first time that Xi has publicly made such a statement, was an important first step for the two nuclear powers to address regarding this long-term strategic risk, according to National Public Radio. 

The private meeting came after Biden misspoke during his public comments to Xi. He initially called the relationship between the two countries an “alliance,” before correcting himself, according to the New York Post. 

“We are the most important alliance – or the most important relationship in the entire world, and how we’re getting along together can impact the rest of the world,” Biden said. 

While expressing concern that President-elect Trump could complicate the relationship between the two countries, Xi offered an optimistic appraisal of the situation. 

“China is ready to work with the new U.S. administration to maintain communication, expand cooperation and manage differences so as to strive for a steady transition of the China-US relationship for the benefit of the two peoples,” Xi said through an interpreter.