SYDNEY - Australia's world-famous Sydney Opera House was evacuated after a suspicious package was found, television channels reported on Monday, soon after gunmen were reported holding hostages in the centre of the city.

A police operation was already underway in the central business district of Sydney after hostages were being held inside a cafe, where a black flag with white Arabic text could be seen in the window.

A spokeswoman for New South Wales police could not immediately confirm the reports. An Opera House spokeswoman did not answer calls.