SHANGHAI - Battle lines have been drawn between China's search engine leader Baidu and Qihoo 360 Technology Co after the latter launched its own search engine challenging Baidu's dominance.

Qihoo, an Internet security service provider, introduced the 360 service on August 16, and the search engine became the country's second-most popular following Baidu within a few days.

On Tuesday, Baidu started to force the redirection of search results from 360 to the Baidu homepage, meaning that users inputting searches into 360 soon end up redirected to Baidu.

Later, Qihoo retaliated by removing some of its sub searches including news, maps and MP3s, which are Baidu's products, and replacing them with its own products and those of search engine rivals Google and Sogou.

According to an official Qihoo announcement on Wednesday afternoon, it is aiming to become an important player in the search engine market and will devote itself to constructing a safe and clean online search market with effective competition.

However, Baidu has kept silence on the affair so far.

Fang Xingdong, board chairman of Beijing-based IT think tank Chinalabs.com., said if Qihoo wins the battle, Baidu's Chinese monopoly will be broken and a post-Baidu era will begin.

According to statistics from Analysys International, a business information provider, Baidu's share of the Chinese search engine market stood at 78.6 percent in the second quarter of 2012, followed by Google with 15.7 percent and Sogou with 2.9 percent.

Internet user "Dark-Moon" posted on Tencent.com that the search experience on Baidu is not a pleasant one, for Baidu's search results are the result of an auction-based ranking that places paid-for results highest, and sometimes it is very hard to find useful information.

Qihoo president Zhou Hongyi said at a conference last week, "Chinese users are not satisfied with mainstream search services currently. In order to provide high-quality services to users, Qihoo has been closely cooperating with Google, but the search experience provided by Google can not reach an ideal level either."

Zhou said that Qihoo's search is based on natural search results, with the aim of providing better services and stimulating competitiveness in the search market by offering more options for the users.

Experts suggested that China should adopt policies to regulate the market so as to promote healthy development of the growing Internet industry.

Analysts also believe that Qihoo's entering into the fray is driven by the rich profits on offer in the market.

According to Analysys International, the market size for China's search engine operators in the second quarter reached 7 billion yuan ($1.1 billion), up 62 percent year-on-year. Baidu's revenue for 2011 was 14.5 billion yuan, with a net profit of 6.639 billion yuan, company results have indicated.