Washington: Kathy Chen, Twitter's first-ever managing director for China, once worked for a company that built internet filtering products along with Beijing's ministry of public security, the media reported on Tuesday.

The clients of CA-Jinchen included the National Computer Network Emergency Response Technical Team, which operates China's Great Firewall.

According to Chen's LinkedIn profile, reports Financial Times, she was chief executive of CA-Jinchen, which she described as a “joint venture company formed by Computer Associates International and ministry of public security of China”.

With CA-Jinchen from 1999 to 2005, her role was focused on the “information security industry, providing products, solutions, security applications, and comprehensive services,” she wrote on her profile.

The micro-blogging site last week appointed Chen as its Greater China managing director, chief executive officer Jack Dorsey said in a tweet.

“A big welcome to Twitter, @KathyChen2016! She joins us as our MD for China!”, Dorsey said.

Since her appointment, Chinese Twitter users have raised eyebrows over Chen's past links to the Chinese government.

Twitter has been blocked in China since 2009. The micro-blogging site currently has over 300 million users.