China has cut its involvement in the Sea-Me-We 6 project as tensions rise between the US and China over the control of the physical infrastructure that transmits the world’s online traffic, according to a report by FT on Friday.

Last year, two of China’s biggest telecoms firms, China Telecom and China Mobile, withdrew their combined investment of roughly 20 percent from the subsea cable project linking Asia with Europe, after a US company was chosen to build the line. This marks a shift in power dynamics in the industry and highlights the growing battle between the two countries over who builds and owns the infrastructure that supports the global internet.

China Unicom, a smaller state-owned company, has remained involved with an unspecified investment, but their withdrawal suggests that the US is now taking the lead in terms of technological infrastructure.

The big concern: The Sea-Me-We 6 project is expected to complete in 2025, and the US has denied permission for several subsea telecom cables that involved Chinese companies or directly connected the US to mainland China or Hong Kong due to national security concerns.

Security experts from the west have suggested that data handled by Chinese companies could be accessible to the Chinese government due to the country’s recent data security law, which demands that domestic businesses and organizations share data with the government in matters concerning national security.

However: Experts fear heightened suspicions between US and China could lead to a decoupling of the internet infrastructure, US companies connecting allied nations, and China investing in much of Asia and Africa.