"We need to address the underline drivers of violent extremism," the UN Secretary-General said at a news conference during the Group of 20 (G20) meeting of world leaders here in the Turkish seaside resort.
He welcomed the renewed sense of urgency to find a solution to the civil war in Syria after the Paris attacks, saying the world had a "rare moment" of diplomatic opportunity to end the violence.
Terrorists, he said, have continued to commit the atrocious acts across the world. "Their inhumanity is clear. Their ideologies are bankrupt... Those who claim to be acting in the name of religion are only harming their religion."
He stressed that the response to these have to be robust and "within the rule", "respecting human rights otherwise we will only fan the fight we are trying to protect."
Yesterday, Prime Minister Narendra Modi had also called on the UN to define terrorism before it is too late so that it becomes clear who is siding with terrorism and who is fighting the menace.
He had urged UN member states to pass the Comprehensive Convention on International Terrorism at the earliest.
Reaching a political settlement in Syria should be a top priority.
"This is not only a crisis of numbers. It is a crisis of global solidarity," Ban said on the refuge crisis and asked European countries not to reduce humanitarian aid.
