China is banning Windows 8 devices from at least some government IT purchases, in a mysterious move that took Microsoft off guard.

The ban came from China’s Central Government Procurement Center, which posted a brief notice last Friday on new requirements for government tenders. Among the demands is that Windows 8 be excluded from the bidding process on computer purchases.

It’s unclear how far-reaching the ban will be. The agency could not be reached Tuesday and the new requirements only concern government purchases for “energy-efficient” IT products, including notebooks, desktops and tablets.

China’s state-controlled Xinhua News Agency, however, was more forceful and said that the government was forbidding the use of Windows 8 after Microsoft recently ended official support for Windows XP. “The Chinese government obviously cannot ignore the risks of running OS without guaranteed technical support,” the Tuesday report said.

Chinese officials have previously stressed that Microsoft should lower the price of Windows. They’ve also said to local press that the nation should develop its own homegrown OS to reduce its reliance on foreign companies.

But the Chinese government has still been a major Microsoft customer. In past years, the nation has been working to purchase licensed software for use in government offices and move away from bootleg copies.

Microsoft said Tuesday that it was surprised to see Windows 8 referenced in the Chinese government notice. But the company added that it was working to ensure all its software meets government procurement requirements.

“We have been and will continue to provide Windows 7 to government customers,” the company said in an email. “At the same time we are working on the Window 8 evaluation with relevant government agencies.”

Windows 8 usage is still low in China, with less than 2 percent market share, according to Internet analytics site CNZZ.com. The OS was built for touchscreens, but some have complained that Windows 8 offers a convoluted interface that mashes together tablet and PC uses.