Alibaba.com's Yahoo China unit has filed an unfair competition lawsuit against the company founded by its former general manager.
Yahoo China says Beijing Sanjiwuxian Internet Technology, which operates the Qihoo.com Web portal, distributed software that reports the Yahoo Toolbar as malware and urges users to uninstall it.
Yahoo Toolbar is available free for download, and includes protection against viruses and malware, as well as easy access to Yahoo services, such as the Yahoo search engine and Yahoo Mail. It also adds tabbed browsing capabilities Internet Explorer.
The software distributed by Sanjiwuxian is called 360safe and violates Chinese laws against unfair competition, Alibaba said in a statement.
The lawsuit was filed in Beijing's No.2 Intermediate People's Court, it said. Alibaba is seeking injunctive relief to immediately and permanently stop the distribution of 360safe, as well as damages and a public apology.
The lawsuit steps up the legal battle between Yahoo China and Qihoo, which was founded by former Yahoo China general manager Zhou Hongyi.
In August, Zhou sued Yahoo China in the same Beijing court, saying the company had insulted and libeled him.