BREAKING: Hostage Crisis Unfolding at Chocolate Cafe in Sydney, Australia

The rise of ISIS-inspired terrorist threats in Australia has been a growing problem. Last September, for example, hundreds of officers conducted a series of raids throughout Sydney and Brisbane that authorities claimed stopped a major terrorist plot in its tracks. More than a dozen suspected terrorists were apprehended and detained.

Now, however, a café in the same city has reportedly been overrun by a lone gunman, and civilians are being detained against their will. A black, Arabic flag has also been put on display:

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.

Prime Minister Tony Abbott said he was convening a meeting of the cabinet's national security committee for a briefing on what he called a hostage situation in Australia's commercial capital.

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 radicalised Muslims or by home-grown fighters returning from the conflict in the Middle East.

Dozens of heavily armed police surrounded the Lindt Cafe in Martin Place, home to the Reserve Bank of Australia, commercial banks and close to the New South Wales (NSW) state parliament.

Local news captured the horrifying scene in real time. Stay tuned for updates.

Recommended

Is This Why Trump Rolled Out a Ton of Controversial Picks? Matt Vespa

Fired FEMA Official Just Dug Herself a Deeper Hole Mia Cathell

UPDATE: Via The Guardian and Ed Morrissey:

A black flag with white writing was put in the window of the cafe. It is not an Islamic State flag. The flag appears to bear the Shahada, an Islamic creed which reads: “There is no god but the God, Muhammad is the messenger of God.” It’s can be a benign symbol and appears across the Islamic world, including on the Saudi Arabian flag. But it has also been embraced by jihadi groups such as Jabhat Al-Nusra, an Al-Qaeda affiliate currently fighting in Syria.

UPDATE: Prime Minister Tony Abbott has released a statement:

New South Wales Police and the Australian Federal Police are currently responding to a reported hostage-taking incident in Martin Place in Sydney.

I have spoken with NSW Premier Mike Baird and offered him all possible Commonwealth support and assistance.

The National Security Committee of Cabinet has also convened for briefings on the situation.

This is obviously a deeply concerning incident but all Australians should be reassured that our law enforcement and security agencies are well trained and equipped and are responding in a thorough and professional manner.

We will provide regular updates as further information becomes available.

UPDATE: More about that flag:

In other words, don't rule ISIS out just yet...

UPDATE: Hmmm:

Hopefully, it stays that way.

UPDATE: Amazingly, several hostages were able to flee to safety. Others, however, are still trapped.

Editor's note: This post has been amended.