Chinese regulators met with managers at Microsoft Corp's offices in four cities, including Beijing and Shanghai, in preparation for a potential probe into whether the company engaged in monopolistic practices, a Chinese news site has reported.

State Administration for Industry and Commerce officials also called on Microsoft in Guangzhou and Chengdu on Monday, the Sina.com news portal said on its website, citing a Microsoft China employee.

Regulators may start a probe into Microsoft's possible monopoly in China's operating system market, Sina.com added, citing another unidentified person. China is stepping up scrutiny of US technology companies, and excluded Windows 8 from a government purchasing order in May. US tensions with China escalated after prosecutors indicted five Chinese military officers for allegedly stealing secrets of American companies.

''Microsoft is happy to answer the government's questions,'' the company said in an emailed statement, without confirming whether authorities had visited its local offices in China.

China said in May it will vet technology companies for potential national security breaches, after the government threatened retaliation for a US indictment of Chinese military officers on cyberspying claims.

A spokesman from the State Internet Information Office, cited by the Xinhua News Agency, said in May that ''governments and enterprises of a few countries'' are taking advantage of their monopoly status and technological edge to collect sensitive information.

Qualcomm Inc. said in November that China's National Development and Reform Commission began an investigation related to an anti-monopoly law. The Chinese government has been stepping up corporate scrutiny as new leadership expands an anti-corruption drive and cracks down on business practices that lead to increases in consumer prices.

Washington Post