The Sydney siege: things that are true and things you should ignore. What we know for sure.

Rumours are swirling around Sydney and across social media about the siege underway in a central Sydney cafe. Here’s what we do and don’t know.

What we do know

• An armed offender has been holding an unknown number of hostages inside the Lindt Chocolat Cafe in Martin Place since about 9.45am on Monday.
• New South Wales police know the identity of the hostage-taker, and he is known to police.
• Police have been in direct contact with the hostage-taker, and are conducting negotiations.
• A number of hostages have been seen with their hands pressed up against the glass of the cafe windows.
• Five people have fled the cafe since the siege began, but it is not clear if they escaped or were freed.
• So far there are no known injuries to hostages; “I understand no-one has been injured, and we are grateful,” Police Commissioner Andrew Scipione said.
• The hostage-taker is “claiming political motivation”, according to Prime Minister Tony Abbott.
• The hostage-taker wants to be associated with Islam, as a black flag with an Islamic creed written on it in Arabic has been displayed in the windows.
• The flag is not the one used by Islamic State.
• The hostage-taker has been described as middle-aged with a beard, and wearing a headband.
• Martin Place, the Sydney Opera House, the State Library and all CBD court houses have been evacuated.
• The National Security Committee of Cabinet has convened twice; Mr Abbott described the incident as “deeply concerning” and offered NSW all assistance possible.
• NSW Health has confirmed that one of the hostages to emerge from the Lindt cafe siege is being treated in hospital. The man has been taken to St Vincent’s Hospital where he is described as being in a satisfactory and stable condition.
• Hostages have contacted a number of media outlets, including the ABC, during the day. Police have asked the media not to reveal the contents of the calls.
• Airspace over Sydney’s CBD was not shut down, despite reports to the contrary.
• People who have information about the situation should call the National Security Hotline on 1800 123 400.
• People who want further information about the situation should call the Public Information Inquiry Centre on 1800 227 228.

What we don’t know

• Precisely how many hostages remain in the cafe. A Lindt Australia executive said about 10 staff and up to 30 customers were inside, but police said the total number was not more than 30. A Seven journalist who said he had a view into the cafe said he saw about 15 hostages.
• The details of the motivation or aims of the hostage-taker, except Prime Minister Tony Abbott’s statement that he is “claiming political motivation”.
• Whether the incident is related to terrorism – although NSW Police are “operating according to our counter-terrorism protocols”.
• Exactly what weapons or explosives the hostage-taker may have access to.
• Whether those people who left the building escaped or were set free.