President Joe Biden invited Russian president Vladimir Putin and China's president Xi Jinping to the first major climate summit of his nascent administration, the Leaders Summit on Climate.

Rivals Putin and Xi are among 40 world leaders that Biden invited to participate in the summit, which he will host virtually on April 22 and 23. The summit will "underscore the urgency – and the economic benefits – of stronger climate action," according to the White House.

The Biden administration intentionally looked beyond its international partners for the talks, an administration official said.

“It’s a list of the key players and it’s about having some of the tough conversations and the important conversations,” the official said, speaking on condition of anonymity to discuss U.S. plans for the event. “Given how important … this issue is to the entire world, we have to be willing to talk about it and we have to be willing to talk about it at the high levels.”

The key themes of the summit will include, according to the White House:

• Galvanizing efforts by the world’s major economies to reduce emissions during this critical decade to keep a limit to warming of 1.5 degree Celsius within reach
• Mobilizing public and private sector finance to drive the net-zero transition and to help vulnerable countries cope with climate impacts. 
• The economic benefits of climate action, with a strong emphasis on job creation, and the importance of ensuring all communities and workers benefit from the transition to a new clean energy economy.
• Spurring transformational technologies that can help reduce emissions and adapt to climate change, while also creating enormous new economic opportunities and building the industries of the future.
• Showcasing subnational and non-state actors that are committed to green recovery and an equitable vision for limiting warming to 1.5 degree Celsius, and are working closely with national governments to advance ambition and resilience; and,
• Discussing opportunities to strengthen capacity to protect lives and livelihoods from the impacts of climate change, address the global security challenges posed by climate change and the impact on readiness, and address the role of nature-based solutions in achieving net zero by 2050 goals. 

Biden's predecessor Donald Trump mocked the science underlying urgent warnings on global warming and the resulting worsening of droughts, floods, hurricanes, and other natural disasters. He pulled the United States out of the 2015 U.N. Paris climate accords as one of his first actions. That makes next month’s summit the first major international climate discussions by a U.S. leader in more than four years, although leaders in Europe and elsewhere have kept up talks. The forum is a return to a practice utilized by both George W. Bush and Barack Obama.

U.S. officials and some others give the Obama administration’s major-economies climate discussions some of the credit for laying the groundwork for the Paris accord. The United States and nearly 200 other governments at those talks each set targets for cutting their fossil-fuel emissions, and pledged to monitor and report their emissions. Another Biden administration official said the U.S. is still deciding how far the administration will go in setting a more ambitious U.S. emissions target.

The Biden administration hopes the stage provided by next month’s Earth Day climate summit — planned to be all virtual because of COVID-19 and all publicly viewable on livestream, including breakout conversations — will encourage other international leaders to use it as a platform to announce their own countries’ tougher emission targets or other commitments, ahead of November’s U.N. global climate talks in Glasgow.

The administration hopes more broadly the session will help galvanize governments on getting moving on specific, politically-bearable ways to retool their transportation and power sectors and overall economies now to meet those tougher future targets.

The U.S. summit isn’t just “about the deliverables, it really is about engaging at the leader level … sending a signal from the U.S. perspective about how serious we are, and putting our own cards on the table in a significant way,” the first official said, referring to Biden’s upcoming announcement on a more aggressive U.S. emissions target. “And hoping that countries will join us.”

Like Bush’s and Obama’s major-economies climate forums, Biden’s invite list includes leaders of the world’s biggest economies and European blocs. That includes two countries — Russia and China — that Biden and his diplomats are clashing against, over election interference, cyber attacks, human rights and other issues. It’s not clear how those two countries in particular will respond to the U.S. invitations, or whether they are willing to cooperate with the U.S. on cutting emissions while sparring on other topics. China is the world’s top emitter of climate-damaging pollution. The U.S. is No. 2. Russia is No. 4.

Brazil is on the list as a major economy, but it’s also a major climate backslider under President Jair Bolsonaro, who derailed preservation efforts for the carbon-sucking Amazon and joined Trump in trampling international climate commitments.

The 40 invitees also include leaders of countries facing some of the gravest immediate threats, including low-lying Bangladesh and the Marshall islands, countries seen as modeling some good climate behavior, including Bhutan and some Scandanavian countries, and African nations with variously big carbon sink forests or big oil reserves. Poland and some other countries on the list are seen as possibly open to moving faster away from dirty coal power.

Biden as a candidate pledged $2 trillion in investment to help transform the U.S. into a zero-emission economy by 2050 while building clean-energy and technology jobs. Biden and other administration officials have been stressing U.S. climate intentions during early one-on-one talks with foreign leaders, and Biden climate envoy John Kerry has focused on speeding up emissions cuts internationally in diplomacy abroad.

Tensions have risen between the U.S. and both Russia and China in recent weeks.

Biden said that Putin will "pay a price" after the U.S. declassified an intelligence report Tuesday that said Russia's president likely directed a campaign aimed at denigrating Biden in the 2020 presidential election, and answered "I do" when asked by ABC's George Stephanopoulos if he thinks Putin is "a killer." The "killer" remark drew swift condemnation from the Kremlin, including from Putin himself.

The U.S. and China sparred in a recent face-to-face diplomatic meeting between American and Chinese officials. At his first presidental press conference on Thursday, Biden said he’s not looking for a confrontation with China but is prepared to engage in “steep, steep competition” with the country. Biden added that fair competition will require the U.S. holding China accountable for its actions.

Biden also said the United States cannot turn a blind eye to China’s human rights violations. 

He said he told Chinese President Xi Jinping, “As long as you and your country continue to so blatantly violate human rights, we are going to continue in an unrelenting way to call to the attention of the world and make it clear what's happening.” 

“The moment a president walks away from that, as the last one did, is the moment we begin to lose our legitimacy around the world,” Biden said, taking a shot at Trump.

Biden said Xi is very smart and straightforward but that he “doesn't have a democratic, with a small "D," bone in his body.” He also said the Chinese president was like Russian President Vladimir Putin in that he “thinks that autocracy is the wave of the future [and] democracy can't function in an ever-complex world.”

The list of world leaders participating in the event is as follows, per the White House:

• Prime Minister Gaston Browne, Antigua and Barbuda
• President Alberto Fernandez, Argentina 
• Prime Minister Scott Morrison, Australia     
• Prime Minister Sheikh Hasina, Bangladesh
• Prime Minister Lotay Tshering, Bhutan
• President Jair Bolsonaro, Brazil    
• Prime Minister Justin Trudeau, Canada           
• President Sebastián Piñera, Chile 
• President Xi Jinping, People’s Republic of China    
• President Iván Duque Márquez, Colombia    
• President Félix Tshisekedi, Democratic Republic of the Congo
• Prime Minister Mette Frederiksen, Denmark 
• President Ursula von der Leyen, European Commission
• President Charles Michel, European Council
• President Emmanuel Macron, France         
• President Ali Bongo Ondimba, Gabon         
• Chancellor Angela Merkel, Germany 
• Prime Minister Narendra Modi, India     
• President Joko Widodo, Indonesia      
• Prime Minister Benjamin Netanyahu, Israel
• Prime Minister Mario Draghi, Italy    
• Prime Minister Andrew Holness, Jamaica
• Prime Minister Yoshihide Suga, Japan  
• President Uhuru Kenyatta, Kenya      
• President David Kabua, Republic of the Marshall Islands
• President Andrés Manuel López Obrador, Mexico  
• Prime Minister Jacinda Ardern, New Zealand
• President Muhammadu Buhari, Nigeria        
• Prime Minister Erna Solberg, Norway 
• President Andrzej Duda, Poland  
• President Moon Jae-in, Republic of Korea     
• President Vladimir Putin, The Russian Federation  
• King Salman bin Abdulaziz Al Saud, Kingdom of Saudi Arabia
• Prime Minister Lee Hsien Loong, Singapore 
• President Matamela Cyril Ramaphosa, South Africa 
• Prime Minister Pedro Sánchez, Spain
• President Recep Tayyip Erdoğan, Turkey
• President Sheikh Khalifa bin Zayed Al Nahyan, United Arab Emirates
• Prime Minister Boris Johnson, United Kingdom
• President Nguyễn Phú Trọng, Vietnam 

The Associated Press contributed to this report.