Researchers over the weekend uncovered a Facebook app for Apple's iPad, and showed how "jailbroken" tablets could run the still-unreleased software.

By Monday afternoon however, Facebook had blocked logins through the iPad app, according to Marvin Bernal, a Toronto computer engineering student who earlier tweeted how to unlock the new software.

"It appears that Facebook has disabled logins through the 'iPad' version," said Bernal in a message on Twitter. "Time to wait for an official release."

According to Bernal and others, Facebook's iPad app is tucked inside version 3.4.4 for the iPhone, which appeared on the App Store last Friday as a fix for several crash bugs and to restore the Send button to several sections of the social networking site.

Rather than post separate files on the App Store for the iPhone and iPad, many iOS developers create a "universal" binary that installs device-specific versions on both.

To access Facebook's hidden iPad app, users had to jailbreak the tablet, then change the "UIDeviceFamily" setting in the iPhone app to "2." Instructions on how to activate the iPad app, including a video walkthrough, were quickly posted on the Internet by the Jailbreak Nation blog.

Facebook did not immediately reply to a request for comment on the hidden app, or the disabling of logins.

The appearance of a universal binary that includes an iPad-specific app may signal that Facebook will soon release the program.

Reports of an imminent Facebook iPad app debut have circulated for some time, but gathered momentum last month when the New York Times, citing unnamed sources, claimed that the company would ship an app in the next few weeks.

Earlier this month, during a press event to introduce Skype integration, Facebook CEO Mark Zuckerberg told reporters that the company was planning to announce several other products in the near future.

"Over the next coming weeks and months we just have a lot of fun stuff to roll out," said Zuckerberg at the start of the July 6 presentation. He did not elaborate on what Facebook would release.