A hostage situation has unfolded over the last hour or so in Sydney, Australia, but it may be a message to the world. An unknown number of perpetrators seized control of a cafe and have a dozen or more hostages, some of which have been apparently forced to display a black flag with Arabic lettering:

Hostages were being held inside a central Sydney cafe where a black flag with white Arabic writing could be seen in the window, local television showed on Monday, raising fears of an attack linked to Islamic militants.

Australia, which is backing the United States and its escalating action against Islamic State in Syria and Iraq, is on high alert for attacks by radicalized Muslims or by home-grown fighters returning from fighting in the Middle East. …

Live television footage showed patrons inside a cafe standing with their hands pressed against the windows. A black and white flag similar to those used by Islamic State militants in Iraq and Syria was also visible.

From initial reports, the hostage situation has unfolded across the street from a television station — which can’t exactly be an accident. The area of Sydney is described as the financial center of the city, which is probably also no accident. However, the flag itself isn’t one commonly used by ISIS, as Buzzfeed points out. That doesn’t mean it’s not directly connected to ISIS, of course, but it may also be a home-grown effort of some sort.

Sydney’s Channel 7, the station across the street from the cafe, has live video coverage of the hostage situation:

We’ll keep an eye on the story for further developments.

Update: The Guardian has more on the flag:

My colleague Michael Safi reports the flag in the cafe window appears to bear the Shahada: “There is no god but the God, Muhammad is the messenger of God.” It is not the Islamic State flag.

He reports:

The flag that hostages appear to have been forced to hold up in the window of the Lindt Cafe in Martin Place is not the Islamic State flag – but that isn’t to say that Isis is not involved in today’s incident.

It could very well be a home-grown group that affiliates itself with ISIS or just shares its terrorist goals. It’s doubtful that ISIS will be unhappy to hear about this, though.

Update: The Daily Mail says it’s a Jabhat al-Nusra flag, which would make this an al-Qaeda operation, but that’s not been confirmed yet either.

Update: (Jazz) Cable networks slowly cutting away from this story, but the video feeds available quote a woman saying that a person with a blue bag, possibly containing a gun, entered the Lindt Cafe shortly before the events unfolded. Still looking for confirmation, but one report on NBC suggests it’s possible that they are dealing with a single perpetrator.

Update (Ed): I’ve been following the story on Twitter, but we’re being cautious with the updates. As longtime readers know, the first reports from a crisis situation almost always turn out to be wrong. We’ll wait for significantly corroborated updates before posting them. Feel free to share what you’re seeing in the comments, of course, but we’ve learned to be cautious about drawing conclusions from data that may change significantly within minutes.

Update (Ed): The police held a press conference a few minutes ago, in which they called the situation “contained” but noted that they have not had direct communication with the perpetrator:

"No contact with #SydneySiege armed offender at this stage": @nswpolice http://t.co/z9JrtJ2IN3 pic.twitter.com/v0ipmuacMP

— BBC Breaking News (@BBCBreaking) December 15, 2014