WASHINGTON: The United States and two other countries hiked their targets for slashing greenhouse gas emissions at a global climate summit hosted by President Joe Biden, an event meant to resurrect US leadership in the fight against global warming.

Biden unveiled the goal to cut emissions by 50%-52% from 2005 levels at the start of a two-day climate summit kicked off on Earth Day and attended virtually by leaders of 40 countries including big emitters China, India and Russia.

The United States, the world's second-leading emitter after China, seeks to reclaim global leadership in the fight against global warming after former President Donald Trump withdrew the country from international efforts to cut emissions.

"This is the decade we must make decisions that will avoid the worst consequences of the climate crisis," Biden, a Democrat, said at the White House.

British Prime Minister Boris Johnson called the new US goal "game changing" as two other countries made new pledges.

Prime Minister Yoshihide Suga, who visited Biden at the White House this month, raised Japan's target for cutting emissions to 46% by 2030, up from 26%. Environmentalists wanted a pledge of at least 50% while Japan's powerful business lobby has pushed for national policies that favor coal.

Canada's Prime Minster Justin Trudeau, meanwhile, raised his country's goal to a cut of 40%-45% by 2030 below 2005 levels, up from 30%.

Chinese President Xi Jinping did not announce a new emissions goal, saying that China expects its carbon emissions to peak before 2030 and the country will achieve net zero emissions by 2060.