Nokia chief exec Stephen Elop has sparked speculation about his company's commitment to its partnership with Microsoft and Windows Phone.

Asked flat out by Spanish daily El Pais if Nokia will produce Android devices, Elop replied "today we are engaged and satisfied with Microsoft, but anything is possible" - an eye-catching ambivalent answer.

Elop, a former Microsoft product bigwig, reaffirmed Nokia's commitment to using the Windows Phone operating system, saying the goal was to build a mobile application ecosystem "equilibrium" or "balance" depending on your choice of translation - a curious phrase either way.

But Elop pointed out that future technology shifts, such as developers using write-once-run-anywhere HTML5 to build software, may make the choice of smartphone platform redundant. He also pointed out that Nokia had rejecting Google's Android operating system because it would have been tough differentiating its products from all the other Android handset makers. This rationale has been borne out by the market: Samsung "became very strong and the others are having a hard time".

Asked if he was concerned by Microsoft launching a rival Windows-powered smartphone, Elop said Nokia had enough technology to differentiate itself: he cited his firm's Maps, CityLens and its imaging technology.

Elop is an experienced media-savvy executive who always choses his words carefully: we can assume that the "anything can happen" riposte was not accidental. The Windows Phone 8 platform gets positive reviews but negligible interest. It certainly needs a lift: it's stronger than a year ago, but to an ordinary user it appears to have gone sideways rather than forward. The Windows Phone Marketplace is arguably the only app store that's emptier than it was a year ago.

However, for Nokia, competing with your partners could be costly. But just how costly?

Microsoft may argue that Google's Nexus phone strategy left room for Samsung to prosper, and Microsoft may believe its Windows 8 Surface touchscreen-laptop has drawn huge attention. Well, maybe.

But it's certainly enough to steal attention from Nokia, which regards itself as Redmond's most-favoured platform partner. Microsoft paid $1bn to help Nokia's risky transition to Windows Phone and continues to support it with platform payments of $250m per quarter - which Nokia admits is slightly higher than the royalties Nokia returns to Microsoft.

Ironically, in the interview Elop justified his brutally honest February 2011 "burning platform" memo in which he signalled the demise of Symbian and the move to Microsoft's Windows Phone, by explaining that "you have to convey a clear and concrete strategy to prevent internal debates".

Debates which, with his latest interview, he just seems to have opened up again. ®