Officials said there is a risk of further flash flooding in Colorado as residents attempt to recover from the worst floods to hit the state for almost 40 years.
More downpours are forecast on Sunday following five days of unprecedented rainfall that has destroyed homes and washed out bridges and roads.
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The prime minister said there was a "clear and urgent imperative" to give new impetus to stalled negotiations.
Pollution claimed nine million lives in 2015, with air pollution from vehicles and factories accounting for 6.5m deaths, researchers found.
Donald Trump has given himself a "10 out of 10" for the response to the widespread hurricane devastation Puerto Rico suffered.