Developing countries have demanded new financial help from wealthy nations in their uphill fight against the climate crisis, during a summit in New York at which U.N. Secretary-General Antonio Guterres said they had "every right to be angry."

Guterres told the one-day Climate Ambition Summit at U.N. headquarters that poorer countries had done the least to cause global warming but were bearing the brunt of its impacts, from more droughts and heat waves to storms and wildfires.

"Many of the poorest nations have every right to be angry," he said. "Angry that they are suffering most from a climate crisis they did nothing to create. Angry that promised finance has not materialized.