Chinese government investigators visited Microsoft offices in four key Chinese cities on Monday, according to a company spokeswoman. However, the reason for the visits was not immediately clear.

Microsoft, like other U.S. technology giants in recent months, has been under fire from Chinese media for its perceived role in helping the U.S government conduct cyber-hacking against China.

On Monday, investigators from China's State Administration for Industry and Commerce —the nation's main business authorities — visited Microsoft offices in Beijing, Shanghai, Guangzhou and Chengdu. Microsoft said the purpose of the visit was to begin an official investigation. It did not elaborate further.

Microsoft China spokeswoman Joan Li said the company would "actively cooperate" with the government, reported the South China Morning Post, a Hong Kong-based newspaper.

The SAIC also provided no further detail about the investigation.

Microsoft enjoys huge sales in China but like many Western companies has also suffered attacks by state media, which have fanned nationalist sentiment against the adoption of U.S. technology in the wake of Edward Snowden's revelations about U.S. government cyber-spying.

In May, Beijing announced that central government offices were banned from installing Windows 8, Microsoft's latest operating system, on new computers. Soon after, China's state broadcaster CCTV ran a critical program suggesting that Windows 8 was being used to seize information on mainland citizens.

This month, CCTV called Apple Inc's iPhone a threat to national security because of the smartphone's "Frequent Locations" function that can track and time-stamp the user's location.

Separately, Fang Xingdong, an Internet and blogging pioneer, wrote in the Global Times tabloid on Monday urging Chinese government and military officials to stop using Apple cellphones.
(USA Today)