Microsoft kept the tech world buzzing Monday ahead of a mysterious announcement which has fueled speculation the software giant may unveil a product to challenge the Apple iPad.

The venue for the invite-only announcement, shrouded in secrecy reminiscent of tech mega rival Apple's media-frenzied unveilings, was disclosed to participants only hours before the event itself.

Journalists -- who last week received an invitation teasingly telling them "This will be a major Microsoft announcement -- you will not want to miss it" -- were told to turn up at the Milk Studios, in downtown Hollywood.

The Milk Studios website describes it as "one of the world's premiere photography studios, (which) stands at the crossroads of fashion, photography, art and media" -- although it was unclear what link it has with Microsoft.

The Hollywood location has fueled speculation that the announcement could involve entertainment industry content.

But beyond the venue there were still few concrete details of what was in store at the 3:30 pm. (2230 GMT) event, which has triggered an array of reports, some contradictory.

Last week, the entertainment website The Wrap said it had learned Microsoft would unveil its own branded tablet powered by Windows in a head-on challenge to Apple.

Technology news site TechCrunch said the announcement would not involve a device with the upcoming Microsoft 8 operating system, but a co-branded tablet with Barnes & Noble, the struggling bookseller and maker of the Nook tablet.

The device, according to TechCrunch, could allow consumers to link to the Microsoft Xbox 360 gaming console for streaming movies and other entertainment.

Microsoft in April announced a $300 million investment in a new Barnes & Noble subsidiary which includes the Nook business.

But the business website Benzinga said Barnes & Noble indicated it was not part of the Microsoft announcement.

The brokerage firm Canaccord said "sources close to the matter" indicate Microsoft would unveil a tablet running the next version of Windows under its own brand, departing from its strategy of partnering with computer makers.

"Microsoft has been working with computer makers in the production of the tablets, looking to win share of the tablet market from the dominant iPad," the brokerage said in a note to clients.

Some others speculated Microsoft might announce a deal to buy online video service Hulu and weave it into the Xbox Live online entertainment service linked to the Redmond, Washington-based company's leading Xbox 360 videogame consoles.

The fact that the press event will be held at a yet-to-be disclosed venue in Los Angeles hinted heavily that entertainment industry content would be in the spotlight.

"It's in L.A., so they are going to talk about media," said independent Silicon Valley analyst Rob Enderle.

"It could be about hardware, but after the Kin failure and the Zune failure I can't picture the person at Microsoft who has the balls to pitch a Microsoft tablet."

Kin was a youth-oriented mobile phone from Microsoft that was pulled from the market after just weeks, while Zune was the longtime Apple rival's now-abandoned MP3 device that unsuccessfully challenged the iPod.

Some analysts were speculating about an early release of Windows RT, the Microsoft operating system to power tablets or other mobile devices running on ARM chips, which allow mobile devices to run more efficiently.

Microsoft earlier this month stepped up its quest to be at the heart of home entertainment by syncing Xbox 360 videogame consoles to smartphones and tablets while adding more blockbuster content.