UN Secretary General Kofi Annan called on Tuesday for sensitivity towards religious beliefs and sacred symbols, warning that mistakes, intentional or not, could trigger a global war of religion.
He said international migration, which brought millions of people of different creed and culture to live together, has not united them.
"The misconceptions and stereotypes underlying the idea of a clash of civilization have come to be more and more widely shared, and insensitivity towards other people's beliefs or sacred symbols - intentional or otherwise - is seized on by those who seems eager to foment a new war of religion, this time on a global scale," Annan said in his address to the UN General Assembly.
Annan said the climate of fear and suspicion is constantly fuelled by violence in the West Asia, carrying a powerful and emotional symbol affecting even those people remote to the conflict between Israelis and Palestinians.
He also said the UN has failed to resolve some of the biggest challenges in the last 10 years: an unjust world economy, world disorder and contempt for human rights and rule of law.
"As a result, we face a world whose divisions threaten the very notion of an international community, upon which this institution stands," he said.
Annan said the address and an annual report he was presenting to the 192-nation assembly would be his last before stepping down on December 31.
The UN failure to resolve world challenges in the last 10 years fell on his watch, Annan said, citing the humanitarian crisis in Sudan's Darfur region and the protracted conflict in the West Asia.
"Yes, I remain convinced that the only answer to this divided world must be a truly United Nations," he said.
Annan said his recent visits to several West Asia governments showed that the UN remains the world's only organisation with "legitimacy and reach".