Yahoo's China arm will shut down its email service later this year, state media reported Friday, illustrating the brand's diminishing profile in the country.

China Yahoo! announced it will close its email service by August 19, a move the China Daily said will leave it with just its web portal business.

Users of the service were informed that they must register with AliCloud, a unit of Chinese e-commerce giant Alibaba, to prevent emails and other information from being deleted when Yahoo's mail service stops.

China Yahoo! has been operated by Alibaba since 2005, the paper said.

The US Internet giant Yahoo! has come under criticism in the past over its business in China, with executives apologising in 2007 for providing evidence that Chinese authorities used to convict government critics.

The company said it was legally obliged to divulge information about its users to the Chinese government but that it was unaware it would be used to convict dissidents.

The end of the service will affect millions of users, the paper quoted Alibaba public relations official Zhang Jianhua as saying, though he did not have a total figure.

The China Daily quoted Zhang as saying the move was because "we are not sure how long we can provide the email service under Yahoo's current technological structure".

In September, Alibaba Group Holding Limited announced that it has bought back billions of dollars worth of stock from Yahoo!, by completing an initial repurchase of shares from the US company and other transactions valued at approximately $7.6 billion.

The move partly fulfilled a previous deal that Yahoo! would sell back its 40 percent stake in Alibaba.

In a statement to AFP, a spokesperson for China Yahoo! confirmed that the email service would be suspended and said: "We will offer several options to our users to make this transition as smooth as possible, and China Yahoo! users will have four months time to migrate their accounts."

The statement said that the migration process had started on Thursday.

Users of China's Twitter-like microblogs expressed anger at the news.

A post under the name "Lisa's paw" said: "How can they do this? All of sudden Yahoo mail can't be logged onto and everything was moved to AliCloud. Did you ask for users' opinions?"