Facebook Inc is setting up a new engineering team in Singapore to focus on its lucrative China advertising business, according to sources, even as chief executive Mark Zuckerberg ramps up criticism of China that blocks the social network.

The team at Facebook’s Asia-Pacific headquarters is tasked with developing better ad-buying tools for Chinese customers who have to work around internet restrictions in China known as the “great firewall,” the sources said. Facebook’s first significant attempt at developing regionally localized ads tools outside of its Silicon Valley headquarters, where China-related engineering work previously took place.

Facebook confirmed the creation of the new team, describing it as having an “Asia-first” mission and consisting of both product and “business integrity” sub-teams. Its existence has not previously been reported. A spokeswoman said the team would serve “Asia as well as our global advertisers.”

Facebook sells more than $5 billion a year worth of ad space to Chinese businesses and government agencies looking to promote their messages abroad, analysts estimate. That makes China Facebook’s biggest country for revenue after the United States, which delivered $24.1 billion in advertising sales in 2018.

Zuckerberg once hoped Facebook could find a way to operate its social network in China, making a high-profile visit to the country in 2016 and vowing to learn Mandarin. Product managers went on “knowledge-exchange” trips to China, swapping expertise on app features and advertising tools with counterparts at companies like Tencent and Alibaba, one source said.

Even though U.S – China trade war is still on Facebook remains eager to expand its China ad business, which boasts customers in industries including fashion, social media and gaming. Facebook is eager to grow its market in China and they are trying hard to get a business entry into the comparatively huge internet market.