China's second-biggest mobile phone company is scrapping plans to use Google's search function on two new phones, while the country's most popular internet portal is reviewing its partnership with Google, executives said Thursday.

An executive with China Unicom, the country's No. 2 mobile company, said the company is shelving plans to use the Google search on two new cellphones running Google's Android software.

In a statement, Unicom President Lu Yimin said, "Google's withdrawal from the mainland market will not affect the company's development of Android phones. Currently our phones have no pre-installed Google search tools."

A spokesman for Sina Corp., which owns the popular Sina.com portal that features a Google search bar on its main page, said top management was evaluating its partnership with Google, but no decision had been made on its future.

"All of our co-operation with Google is based on two things: one is that Google complies with China's laws and the other is that it has its long-term business operation plans in China," said Chen Jinguo.

Tianya.cn, a popular portal that claims 32 million registered users, said it was taking full control over social networking and question-and-answer services operated jointly with Google.

A company spokesman declined to say whether the government exerted pressure, but said in a statement that the takeover was being done to "guarantee each product, normal business and good operations."

Google officials in the U.S. didn't immediately respond to requests for comment. A company spokeswoman in Tokyo, Jessica Powell, said Google had been "working with Tianya over the last couple of months to phase out this partnership in favor of our own offerings."

Industry executives said Google's China revenues were diving as companies shied away from placing new ads with the search engine.

Powell, the Google spokeswoman, said Wednesday the company was continuing to work with Chinese business partners, even providing some with censored search services to abide by existing contracts.

Setting up a search engine on Chinese soil four years ago helped Google build new business relationships. But those alliances have started to fracture since Monday, when Google started to redirect search traffic from mainland China to an uncensored Hong Kong service.

Though part of China, Hong Kong has a semiautonomous status because of its history as a British colony, and Google is not legally required to censor results there.