China's top climate envoy told a UN summit Tuesday his country would not retreat from the fight against global warming, a day after Beijing and Washington were urged to boost efforts.

"Energy and food crises have hit the world one after another, and the climate action process is facing serious challenges," Xie Zhenhua said at the gathering of some 100 world leaders at the United Nations COP27 climate summit in Egypt.

"China has been actively responding to climate change with sustained and pragmatic actions," he added.

"China's determination of actively participating in global climate governance will not retreat, let alone change."

But efforts to make progress against global warming were dealt a blow in August when China suspended climate cooperation with the United States following House leader Nancy Pelosi's visit to Taiwan.

The world's two largest polluters last year pledged to work together to accelerate climate action this decade, and vowed to meet regularly to tackle the crisis.

Xie said that "multilateralism, solidarity and cooperation are necessary to address climate change."

UN chief Antonio Guterres told the summit on Monday that China and the United States have a "particular responsibility" to join a "historic pact" to redouble efforts to speed up the transition away from fossil fuels.

Xie said China "hopes that developed countries will take the lead in effectively scaling up their emission reduction targets and achieving carbon neutrality ahead of time."

While China is the world's second biggest economy, the country has insisted that it cannot be put in the same category as developed countries, as it has had to lift tens of millions of people out of poverty.

AFP