Microsoft will allow Android and iOS apps from rivals Google and Apple to run on its Windows 10 operating system later this year to attract users to its mobile devices.
Operating systems boss Terry Myerson made the announcement at the Microsoft Build developer conference, where he officially confirmed the Windows Mobile moniker for phones and tablets with smaller than eight-inch screens.
He said Windows Mobile will use the Project Astoria subsystem which enables the devices to run apps written for Android in C++ and Java using a runtime layer, without recompiling.
Android apps would still use extensions provided by Windows Mobile, Myerson said.
For example, an Android restaurant-finding app would automatically use Microsoft's Bing maps for directions rather than Google's maps, as it would on an Android phone.
Android developers will be able to use Microsoft technology such as the Cortana personal assistant in their apps as well.
That is a crucial distinction because Google gets revenue from ads on services rather than from the Android system itself.
iOS developers will need to do more work to publish their apps for Windows Mobile users.
Myerson said Microsoft had coded Apple Objective-C toolchains and a layer that supplies the operating system application programming interfaces that iOS apps need to work under the Project Islandwood umbrella.
Project Islandwood lets developers build their iOS apps for Windows Mobile with minor changes to the code.
The move marks a radical shift in strategy for the world's biggest software company, which still dominates the personal computer market but has failed to get any real traction on tablets and phones, partly because of a lack of available apps.
Microsoft has found itself in a circular trap, as many developers will not build apps for Windows phones which have few users, and few people want the phones as they have fewer apps than Android or Apple phones.
Allowing Android apps onto its phones and tablets could be a shortcut to breaking out of that trap. But the strategy runs the risk of making Windows phones less attractive if they are merely seen as emulations of Android devices.
"The only approach to succeed today is to recognise the multiple developer ecosystems out there," said Al Hilwa, an analyst at tech research firm IDC.
Google declined to comment. Apple did not immediately respond to requests for comment.
Microsoft, which bought Nokia's handset business last year, has only three percent of the global smartphone market. By contrast, Android phones, led by Samsung, control 81 percent of the market and Apple 15 percent, according to Strategy Analytics.
Microsoft is scheduled to release its new Windows 10 operating system this summer, which for the first time will run across PCs, tablets and phones.