Chinese officials confirmed on Tuesday that Microsoft is being investigated for possible violations of antimonopoly laws.

China's State Administration for Industry and Commerce searched four Microsoft offices to seek information on how the tech giant bundles their Windows and Office software. Officials said they've received complaints since 2013 about compatibility issues in Microsoft's software.

According to the Wall Street Journal, the agency talked to the senior executives and staff from the marketing and accounting departments. The officials also confiscated two computers, copies of contracts and financial reports, emails and other files.

Microsoft refused to comment on the issue, but public relations official Joanna Li confirmed that the authorities went to their offices in Beijing, Shanghai, Guangzhou and Chengdu.

"There was a visit from government officials to our offices. Given the sensitivity of the issue, I can't say any more," Li told the New York Times in a phone interview.

The sudden tension between China and the U.S. tech companies might have stemmed from surveillance issues between the two countries. Earlier this month, Chinese television giant CCTV accused Apple of adding a tracking feature in the iPhone to record people's activities and leak state secrets. It also criticized other U.S. companies, including Facebook, Google and Microsoft for allegedly cyber spying and hacking the Chinese government system. Apple denied the allegations.

Other U.S. companies under scrutiny by the Chinese government include Qualcomm and IBM, but Microsoft is the most heavily targeted after being mentioned by former NSA contractor Edward Snowden in the U.S. government surveillance program.

"It's a combination of punishment and paranoia," said James Lewis, a cybersecurity expert at the Center for Strategic and International Studies, to the New York Times. "The Chinese government has always been suspicious of U.S. I.T. products and is using Snowden as an excuse."