Sydney, Dec 15 (ANI): Hostages have been held inside a central Sydney cafe in Australia on Monday where a black flag with white Arabic writing was seen in the window, raising fears of an attack linked to Islamic militants. Patrons were seen 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. Part of Martin Place, home to the Reserve Bank of Australia, commercial banks and close to the New South Wales (NSW) state parliament, has been cordoned off by the armed Australian police. Trains and buses have come to a halt and roads have been blocked in the area. Australian Prime Minister Tony Abbott called an emergency meeting of the cabinet's national security committee.