BEIJING (AP) — Chinese Twitter users have expressed concerns over the company's appointment of a greater China regional executive who has a background working with China's military and state security apparatus.

Kathy Chen was appointed last week to be Twitter's first managing director for China, based in Hong Kong, to oversee advertising.

Since then, Chinese users of the U.S. microblogging site have raised concerns over Chen's connections to Beijing and wondered if their freedom of speech on the platform would be compromised.

Although blocked in China, Twitter is a popular platform for Chinese — especially those living overseas — to freely express themselves in their native language.

Chen once worked for a military research institute and at a company with state security connections. She has not openly responded to Twitter user concerns.