New Delhi, Dec 15 (ANI): Reacting on hostage of unknown number of people in Sydney cafe, Security experts on Monday said that this raises concern of terrorist involvement in the mater. Praful Bakshi said that the world need to look at the threat completely as people belonging to same religion of ISIS are following them at massive scale. Uday Bhaskar said that said that the incident poses threat to civil society. Meanwhile, Major General (retd.) SR Sinho said terrorists through the Sydney hostage crisis are sending out a message to important nations of the world that this is what they can do. Sinho said Australia until now was peaceful and the terrorists have by this activity sent a message that now they can go out anywhere in the world. He said the attack is a threat to India also as it is the most vulnerable country.