A major element of China’s continent-spanning Belt and Road Initiative has nothing to do with roads, ports or power plants. Rather, the “Digital Silk Road” aims to construct communications networks across the developing world.

Many fear Beijing could use those tools for electronic surveillance.

The world’s second-largest economy wants to build cables, mobile structures and e-commerce links in countries tied to its investment initiative, most of which are emerging economies and lack rudimentary internet facilities. Those technologies are designed to supplement the Belt and Road’s physical infrastructure while boosting connectivity and introducing common technical standards in poor nations.

A 2015 white paper jointly released by various Chinese government bodies explained the initiative in part by saying a unified approach to infrastructure connectivity can enable information exchanges, bringing about “mutual benefit and win-win cooperation.”

But there are geopolitical implications if foreign governments allow Chinese technology companies — believed to carry close ties with the state — to install such digital systems.

A big fear is that Chinese players will insert “backdoor mechanisms that could increase [Beijing’s] intelligence and propaganda operations in BRI partner countries,” researchers at the Council on Foreign Relations said in a note last week.

State-owned China Mobile, the world’s biggest telecom carrier by subscriber count, is currently building optical fiber cable projects linking Beijing to Myanmar, Nepal and Kyrgyzstan. Meanwhile, private player Huawei signed a deal last year to build a cable system linking Pakistan to Kenya via Djibouti. Talks are also underway for state-owned China Telecom to help build fiber-optic links in the Arctic Circle.

Cables, which transfer massive amounts of personal, government and financial data, are controlled by telecommunications firms. So, when it comes to enforcing security, regulatory grey areas emerge.

That infrastructure can be used to help Beijing gain information, according to the Council on Foreign Relations. For example, technicians can bend or clamp the fibers to allow data to leak out or bypass encryption, the note explained: “Prior actions taken by the Chinese government, such as installing backdoors in encryption technology, suggest that it will take similar actions when laying down fiber optic cables in other countries.”

China Mobile, Huawei and China Telecom didn’t respond to CNBC’s requests for comment.

Chinese companies are also involved in deploying 5G mobile technologies worldwide under the Digital Silk Road. Chinese development banks provide loans to fund mobile network-building projects in cash-strapped countries, and that financial support gives Beijing leverage to help Chinese companies secure new markets.

While those projects may benefit developing economies, “they have raised concerns that Beijing could use these networks to exert pressure on other states or engage in electronic surveillance,” The Economist Intelligence Unit said in a recent report. “BRI countries will need to enhance regulatory frameworks and oversight of projects to mitigate financial risks and political dependence,” it added.

At the heart of the matter is deep-rooted suspicion about the data-sharing practices of Chinese firms. Tech heavyweights could be legally required or co-opted to support and participate in Chinese intelligence, said Elsa Kania, a Fulbright specialist at the Australian Strategic Policy Institute.

“That raises concerns about the implications for China’s future espionage capabilities, while also creating leverage that could be exercised for coercive purposes,” she explained.