Moderna Inc. will push toward producing messenger RNA vaccines for China, seeking a foothold in the world’s second-largest pharmaceutical market even as geopolitical tensions rise.

Moderna signed a memorandum of understanding and land collaboration agreement on Wednesday to work toward researching, developing and producing mRNA vaccines in China, according to a statement. The US-based developer of an mRNA vaccine for Covid-19 may invest around $1 billion, local media outlet Yicai reported Tuesday, citing sources it didn’t identify. Moderna declined to comment on the size of its investment.

Any medicines produced under the deal will be only for the Chinese market and won’t be exported, the Cambridge, Massachusetts-based drugmaker said. The agreement targets unmet needs for Chinese patients, Moderna said.

The investment comes days ahead of a high—profile visit to China by Treasury Secretary Janet Yellen as the US seeks to mend ties and reinstate lines of communication with officials in Beijing. Tensions between the world’s two biggest economies have escalated over a range of issues from national security to a heavy reliance on Chinese supply chains.

Read More: Yellen Heads to China This Week Advancing US Bid to Fix Ties

--With assistance from John Liu.