President Xi Jinping called for concrete cooperation among countries to advance mutual trust and collective governance in cyberspace in his congratulatory letter to the three-day Fifth World Internet Conference, which kicked off in Wuzhen, Zhejiang province, on Wednesday.

The world is going through a broader and deeper science and technology revolution and industrial transformation, Xi said in the letter.

Despite different conditions and challenges, countries across the world share the need to promote the digital economy, interest in handling the challenges of cybersecurity and the demand for better governance in cyberspace, Xi said.

More efforts are needed to speed up development of the digital economy and promote the global internet governance system to advance in a more equitable and reasonable way, so as to inject new impetus into the world economy, Xi added.

The remarks came as the world's internet expansion is on a fast track with the global internet penetration rate hitting 54.4 percent. The figure for China was 57.7 percent as of June 2018.

Huang Kunming, a member of the Political Bureau of the Communist Party of China Central Committee, said such figures mark substantial progress, but it also indicates that nearly half of the global population still does not have access to the internet.

"We need to beef up construction of network infrastructure and narrow the digital divide between different countries and regions," said Huang, who is also head of the Publicity Department of the CPC Central Committee.

As artificial intelligence, quantum computing and other cutting-edge technologies are gathering momentum and becoming increasingly intertwined with other sectors, it is important to support small and medium-sized enterprises to maintain the vitality of the digital economy, Huang said.

Pony Ma, chairman and CEO of Chinese internet giant Tencent Holdings, said that in China, over 98 percent of the more than 800 million netizens are accessing the internet through mobile devices, which is an opportunity for both Chinese and foreign enterprises. "It is our responsibility to create a digital world of mutual trust and collective governance. In the face of challenges, we are not competitors but teammates," he added.

The global digital economy is expected to hit $23 trillion in 2025, according to a report released by Chinese tech company Huawei Technologies Co.

Noting that the internet has revolutionized the production, distribution and consumption of many products and services, Francis Gurry, director general of the World Intellectual Property Organization, said the world also needs to better address challenges that can come with a thriving digital ecosystem.

Robert Lawrence Kuhn, chairman of the Kuhn Foundation, an organization dedicated to promotion of social and cultural exchanges between China and the United States, said Xi's letter "set the tone and gave the overarching vision of really a new world".

He said the internet needs to be made to benefit humanity, and its growth must be sustainable, he said. There are enormous opportunities for economic development, but there are also a whole series of challenges in terms of cybersecurity, which requires global cooperation.

Xinhua and Cheng Yu contributed to this story.