A bipartisan group of US lawmakers is calling on the Biden administration to limit China’s access to a budding technology used to design semiconductor chips, which have become a key technological battleground between Washington and Beijing. 

Eighteen lawmakers urged Commerce Secretary Gina Raimondo to impose export controls on RISC-V technology, an open-source model for code that software uses to communicate with semiconductors. Although RISC-V hasn’t yet been widely used in processors that run computers and phones, interest and support from large companies such as Qualcomm Inc. has raised its prospects.

Critics say RISC-V represents a way for China to develop and exploit a new semiconductor ecosystem free from oversight by Washington. The US has been trying for years to stifle China’s semiconductor industry, most recently by tightening controls on exports of advanced chips and chipmaking equipment to the Asian superpower and adding two Chinese chip design firms to a trade restriction list. 

The lawmakers want a requirement for US firms to obtain a license before sharing RISC-V tech with China. “Urgent action is needed to prevent US technology and technical know-how” from helping China use the technology, wrote the lawmakers, led by Republican Senator Marco Rubio and Representatives Mike Gallagher and Raja Krishnamoorthi, the chairman and ranking member of the House Select Committee on China.