Hostages reported in armed robbery situation inside café in Martin Place, Sydney – @dailytelegraph http://t.co/p7Z19DDeJ1

— Breaking News (@BreakingNews) December 14, 2014

#estápasando: @BlogsofWar A man with shotgun is holding several people hostage in #Sydney: http://t.co/nYEaz3gjij pic.twitter.com/POfDUryDXz

— Fernando Fernández (@ffdezalcaide) December 14, 2014

Terrifying photo of hostages in Martin Place in Sydney, being held by men waving an ISIS flag pic.twitter.com/6ozBRQVNlG

— Tom Steinfort (@tomsteinfort) December 14, 2014

MARTIN PLACE SIEGE: Reports there are 50 hostages inside the shop http://t.co/BhKQFTu08B pic.twitter.com/XP0F119CHN

— The Daily Telegraph (@dailytelegraph) December 14, 2014

RT @australian: Hostages holding up an Islamic flag during the Martin Place siege. pic.twitter.com/61CTNPwHRq

— nikkprecel (@nikkprecel) December 14, 2014

The Sydney Opera House has allegedly been evacuated after the discovery of suspicious package.

— James J. Gorman (@jamesjgorman) December 14, 2014

BREAKING: REPORTS SYDNEY OPERA HOUSE HAS BEEN EVACUATED.

— Mackenzie Price (@mackenziepricee) December 14, 2014

Sydney Opera house evacuated police ambulance arriving

— offtheteam (@tcookAU) December 14, 2014

FROM SEPT: "Police claim they were foiling alleged plan to kidnap someone in Martin Place at random" 7 News on raids http://t.co/tZ49xzqo2u

— Latika Bourke (@latikambourke) December 14, 2014

Police believe there may be an explosive device present in the Sydney Siege. #MartinPlace #Sydney

— Kobi J A VanBennekom (@Jakobi) December 14, 2014

13 hostages inside reporting Channel Seven. #sydneysiege

— Christmas Ham D (@SamCD01) December 14, 2014

Channel 7 reporting confirmed 13 hostages.

— Damien Walker (@DamienCWalker) December 14, 2014

Not an ISIS flag, but generic Islamic flag in the #SydneySiege. Scary world out there.

— Marla (@zoyaroses) December 15, 2014

Flag hostages holding NOT the ISIS flag but bears Islamic message. http://t.co/CXc116fTYT #SydneySiege

— Meg (@sassylibrarian1) December 15, 2014

ABC 24 reporting that it's an ISIS flag now as well. It's not an ISIS flag. #SydneySiege

— Denham Sadler (@denhamsadler) December 15, 2014

Helicopters flying around opera house because they found something suspicious #sydneysiege pic.twitter.com/wbodAJYsLa

— Ellen // The Vamps (@Ellenquinny) December 15, 2014

#sydneysiege Martin Place, Opera House and surrounding areas evacuated. Trains between Central & Bondi stopped. Sydney CBD airspace closed

— Slayer, The (@mockingejay) December 15, 2014

Airspace above central Sydney closed http://t.co/5aA0LM2j3a #SydneySiege pic.twitter.com/sNmRPSNuHq

— Stuff.co.nz News (@NZStuff) December 15, 2014

"…a presenter @ 2GB radio station, is saying the hostage takers want to talk to the PM, Abbott, live on air." #Sydney http://t.co/5eortt83p4

— Erin (@sqwerin) December 15, 2014

Correction: Deputy Australian PM says airspace over #Sydney not closed, helicopters in the air to redirect traffic

— Matt Vespa (@mVespa1) December 15, 2014

"The Deputy Prime Minister’s office has refuted reports Sydney’s airspace is closed. The airspace over Sydney CBD is not in shut down"

— Pablo Rodríguez (@Suanzes) December 15, 2014

Hostages in Sydney cafe brandishing black Shahada flags – identical to those used by ISIS. Our rolling coverage – http://t.co/f8dSKip6Ex

— 7 News Sydney (@7NewsSydney) December 14, 2014