SHANGHAI, Aug 10 (Reuters) - Chinese authorities have arrested a top public relations executive at Chinese social media giant Weibo Corp (WB.O), local Chinese media reported widely on Tuesday and confirmed to Reuters by a company source. According to an internal memo sent to staff and seen by Reuters, Mao Taotao, director of public relations at Weibo - which is partly owned by e-commerce giant Alibaba Group Holding Ltd. - is suspected of bribery and had "seriously harmed the interests of the company." "In accordance with company policy and the law, we have decided to fire Mao as punishment, and will not re-hire him," the memo said. The firing comes as Alibaba (9988.HK) faces backlash over delaying action relating to an employee"s allegations of sexual assault against her manager and a client. On Monday, Alibaba announced the manager had been fired. Mao joined Weibo in 2010 and quickly rose through the ranks of the marketing and PR department, the memo states. Weibo did not respond to a request for comment from Reuters. Mao could not be immediately reached. Weibo has come under fire lately in the wake of a scandal involving Chinese-Canadian pop singer Kris Wu, who Chinese authorities arrested on allegations of soliciting sex with underage girls. Wu has denied the allegations. Not long after Wu"s arrest, state media outlet People"s Daily published an op-ed admonishing social networks for over-hyping celebrities to generate traffic. Weibo later suspended a widely used feature that ranks celebrities by popularity. read more Alibaba did not immediately respond to a request for comment about Mao"s firing at Weibo.