7:31 UPDATE by Mary Chastain: The suspects’ intentions are unclear, though sources have told Australia’s news.abc.au that the men taking the café hostage are allegedly demanding to speak to Prime Minister Tony Abbott live on the radio.

Black Islamic flag being held up in window of #lindt chocolate store in Martin Place, Sydney – hostages inside. pic.twitter.com/fAV7PEuY6P

— Andrew Denney (@Andrew_Denney) December 14, 2014

“@Breaking911: Buildings on Lockdown Around #martinplace #Sydney Hostage Crisis @JakeSturmer pic.twitter.com/pYym7ZziDW http://t.co/gHV5dWyoDw”

— Mike Redding (@ReddingWriting) December 15, 2014

Sydney Opera House evacuated after suspect package found https://t.co/aQp2Q9eUhN #sydneysiege

— Yasmin (@yasminancona) December 15, 2014

The Sydney Opera house has been evacuated following the siege at Martin Place.

— Evana (@evana_abade) December 15, 2014

People and media are gathering behind “safe” barricaded part of #MartinPlace, #Sydney. pic.twitter.com/KT8M90eWuu

— αηιs (@H0XH4) December 15, 2014

VIDEO: Hostages in Sydney cafe forced to raise Islamic flags http://t.co/4eE1IMp2jA pic.twitter.com/jAnV4Nxmqc

— Connor Ryan (@connortryan) December 15, 2014

7:07 PM UPDATE: (AFP) Hostages were being held inside a cafe in central Sydney Monday with a siege underway and an Islamic flag held up to a window, reports and witnesses said.

Martin Place in the central business district was shut down as scores of police surrounded the Lindt Chocolat Cafe, with TV pictures showing a flag, black with white Arabic writing, held to a window.

BREAKING: Hostages are being forced to hold an ISIS flag at a Lindt cafe in Sydney’s Martin Place, as police man the doors outside #7NEWS

— Kristy Mayr (@KristyMayr7) December 14, 2014

Sydney Australia: Not technically ISIS flag but Shahadah flag with Islamic creed on it. Commonly used by militants: pic.twitter.com/s7kg2wSrlQ

— Mubin Shaikh (@CaliphateCop) December 14, 2014