GOOGLE Inc's share in the Chinese mainland mobile search market plunged by half in the first six months of this year after the world's biggest online search engine withdrew from the market, a Beijing-based information technology research firm said yesterday.

Google's market share in China dropped to a record low of 12.3 percent at the end of June, from 23.6 percent a year ago. Baidu.com Inc is still the market leader with 34.3 percent, followed by Shenzhen-based Easou's 16.9 percent. Easou overtook Google China in the period to rank as second in the industry, Analysys International said.

"Google China's market share for mobile search in China has been declining sharply, which caused further changes in the market," Analysys said.

In January, it unexpectedly threatened to quit from the mainland market because of government's search result censorship requirement. In March, Google started to redirect Chinese mainland users to its uncensored Hong Kong search site. The move had caused uncertainty in Google China's business and caused its clients and partners to migrate to rival companies, industry insiders said.

Top handset makers Nokia and Motorola have cooperated with Baidu to provide built-in mobile search services in the domestic market. Motorola phones are even equipped with Android, a mobile operating system developed by Google.

In the global mobile search market, Google dominates with more than 90 percent share. It's the built-in search system for top mobile phones, including iPhone.