The United States and China have agreed to cooperate with other countries to curb climate change, just days before US President Joe Biden hosts a virtual summit of world leaders to discuss the issue.

The agreement between the world’s largest two polluters was reached by US climate envoy John Kerry and his Chinese counterpart Xie Zhenhua during two days of talks in Shanghai last week, the US State Department said in a statement.

“The United States and China are committed to cooperating with each other and with other countries to tackle the climate crisis, which must be addressed with the seriousness and urgency that it demands,” the joint statement said.

China and the United States are the world’s top carbon polluters, pumping out nearly half of the fossil fuel fumes that are warming the planet’s atmosphere.

Their cooperation is key to a success of global efforts to curb climate change, but frayed ties over human rights, trade and China’s territorial claims to Taiwan and the South China Sea have been threatening to undermine such efforts.

According to the joint statement, the two countries will enhance “their respective actions and cooperating in multilateral processes, including the United Nations Framework Convention on Climate Change and the Paris Agreement”.

It said both countries “are firmly committed to working together and with other Parties to strengthen implementation of the Paris Agreement”.

Mr Kerry’s Shanghai trip marked the highest-level travel to China by a US official since Mr Biden took office in January.

From Shaghai, the former secretary of state flew to South Korea for talks.

Mr Biden has invited 40 world leaders, including Chinese President Xi Jinping, to the April 22-23 summit.

The US and other countries are expected to announce more ambitious national targets for cutting carbon emissions ahead of or at the meeting, along with pledging financial help for climate efforts by less wealthy nations.

It was unclear during Mr Kerry’s visit how much it would promote US-China cooperation on climate issues.

When Mr Kerry was still in Shanghai, Chinese Vice Foreign Minister Le Yucheng signalled on Friday that China is unlikely to make any new pledges at next week’s summit.

“For a big country with 1.4 billion people, these goals are not easily delivered,” Mr Le said during an interview with The Associated Press in Beijing.

“Some countries are asking China to achieve the goals earlier. I am afraid this is not very realistic,” he added.

On whether Mr Xi would join the summit, Mr Le said: “The Chinese side is actively studying the matter.”

Mr Biden, who has said that fighting global warming is among his highest priorities, had the United States rejoin the Paris climate accord in the first hours of his presidency, undoing the withdrawal ordered by predecessor Donald Trump.

Major emitters of greenhouse gases are preparing for the next UN climate summit taking place in Glasgow in November.