The head of the United Nations warned the gathered leaders of nations Tuesday that impunity, inequality and uncertainty are driving modern civilization toward “a powder keg that risks engulfing the world” — the latest in an increasing number of clarion calls from Antonio Guterres in recent years that the global situation is becoming intolerable and unsustainable.

Annual meeting of world's leaders opens at U.N. General Assembly at a fraught moment in global politics.

"We can't go on like this," he said as the General Assembly's annual debate among presidents, prime ministers, monarchs and other leaders began. Citing deepening geopolitical divisions, wars with no end in sight,