Beijing will return giant pandas to Washington's National Zoo by the end of the year, US First Lady Jill Biden and officials said Wednesday in a surprise announcement signaling a new era of panda diplomacy between the two superpowers.

"We are excited for children near and far to once again enjoy the giant pandas' adorable and joyful adventures at our @NationalZoo," the first lady posted on X.

China will send a new pair called Bao Li and Qing Bao under a 10-year breeding and research agreement, the zoo said in a statement, hailing a "historic moment" that demonstrated the benefits of its partnership with Beijing.

"We're thrilled to announce the next chapter of our breeding and conservation partnership begins by welcoming two new bears, including a descendent of our beloved panda family, to Washington, DC," said Brandie Smith of the Smithsonian's National Zoo and Conservation Biology Institute. 

"This historic moment is proof positive our collaboration with Chinese colleagues has made an irrefutable impact. Through this partnership, we have grown the panda population, advanced our shared understanding of how to care for this beloved bear and learned what’s needed to protect wild pandas and preserve native habitat." 

Amid soaring tensions between Washington and Beijing, only a handful of the iconic black and white bears remain in the United States, with three having left the national zoo in Washington six months ago.

But President Xi Jinping said after meeting President Joe Biden at a summit in California last November that China could send new pandas as "envoys of friendship between the Chinese and American people."