Senior officials from China and the United States, the world's two largest economies and greenhouse gases emitters, agreed on Friday to intensify their cooperation on climate change.

"On the basis of existing cooperation between the two countries, we will further explore areas and programs with potential for further cooperation," said Xie Zhenhua, vice-minister of the National Development and Reform Commission, after a meeting with Todd Stern, the US special envoy for climate change.

The meeting came just days before President Xi Jinping and his US counterpart President Barack Obama are due to meet in California.

"We will expand cooperation both in band and scope, and work with each other to solve difficulties," added Xie.

Xie and Stern are leading the Climate Change Working Group, which was initiated after the visit of US Secretary of State John Kerry to China in April.

The working group has been deciding and finalizing ways in which the two countries can work closely together on technology, research, conservation, and alternative and renewable energy.

"The establishment of the working group shows that the leaders attach great importance to the issue of climate change, and regard the issue as an important content of bilateral relations.

"Climate change will become a new highlight of the Sino-US bilateral relationship," Xie said.

Stern said that "forceful cooperative action between the US and China is more critical now than ever", adding that "such action will be good for each of the countries individually, and good for the whole world".

Xie and Stern will meet again in China on June 18, before the group's results and recommendations are presented to the fifth Strategic and Economic Dialogue, which is to be held in Washington DC on July 8.

Experts said the joint action taken by China and the US, the two largest greenhouse gase emitters, on how to address climate change was a profound step.

China and the US together emit about 40 percent of global greenhouse gas emissions.

He Jiankun, director of the Institute of Low Carbon Economy at Tsinghua University in Beijing, said such an initiative would be significant for promoting global ecological security and sustainable development.