President Joe Biden has invited his counterparts Xi Jinping of China and Russia's Vladimir Putin to a virtual climate summit he is hosting in April, the White House announced on Friday.

In all, 40 world leaders have been asked to attend the two-day meeting meant to mark Washington's return to the front lines of the fight against man-made climate change, after former president Donald Trump disengaged from the process.

"They know they're invited," Biden said of Xi and Putin. "But I haven't spoken to either one of them yet."

The start of the summit on April 22 coincides with Earth Day, and will come ahead of a major UN meeting on climate change scheduled for November in Glasgow, Scotland.

It is being staged entirely online due to the coronavirus pandemic.

Biden kept his campaign pledge to rejoin the Paris climate agreement on his first day in the White House, after Trump pulled out of the deal.

The return of the world's largest economy and second-largest emitter of carbon dioxide became effective on Feb. 19, and means almost all the world's nations are now parties to the agreement signed in 2015.