Microsoft Corp. has issued a statement outlining its position on essential patents for industry standards, just as an Apple Inc. letter on the same subject was disclosed.

Both companies supported the idea of international standards guiding the licensing of patents for technology used in devices such as mobile phones, tablets and computers.

Microsoft said that international standards work well because companies then promise to share their essential patents on fair and reasonable terms.

"Consumers and the entire industry will suffer if, in disregard of this promise, firms seek to block others from shipping products on the basis of such standard essential patents," the company said in its statement.

The statement followed the disclosure of a letter from Apple Inc. asking for international telecommunications standards to be established, guiding how companies license their patents.

Both moves came as legal battles mount around the world over mobile technology ownership. Apple sent a letter on the issue in November but it was not previously disclosed.

Microsoft (NASDAQ: MSFT) called industry standards "vitally important to the development of the Internet and to interoperability among mobile devices and other computers" and pledged to "always adhere to the promises it has made to standards organizations to make its standard essential patents available on fair, reasonable and nondiscriminatory terms."

Apple's (NASDAQ: AAPL) letter to the European Telecommunications Standards Institute offered suggestions for setting royalty rates for licenses. It said the industry now doesn't have a consistent licensing policy for mobile patents, leading to costly litigation.

Groups like the one Apple addressed often require patent holders to offer to license technology that has become an industrywide standard.

Companies don't usually disclose what they charge for royalties, but in a letter to a California court, Apple said that Motorola Mobility Holding Inc. is seeking 2.25 percent of revenue from sales of iPads and iPhones for technology it uses. That has been estimated to be worth about $1 billion last year and billions more in the future for Motorola and its prospective buyer, Google Inc. (NASDAQ:GOOG).