(AP)—Most of the world's urgent problems boil down to water and sanitation, and global leaders must act to reduce child mortality and urban poverty, the UN's deputy chief said Friday.

There are 783 million people who lack access to clean or relatively safe and 2.5 billion people, or 37 percent of the world's population, who don't have access to toilets, ," Jan Eliasson told reporters on the sidelines of a European Union-Latin America-Caribbean summit in Santiago.

"This is the main reason why more than 3,000 children under 5 years of age die every day from diarrhea, dysentery, dehydration and cholera," he said.

Eliasson said about 60 percent of the world's population will be living in cities in the next 8 years and he's increasingly worried about water issues related to urbanization as more poor people move to capitals with systems.

The career diplomat and former Swedish foreign minister pointed to examples such as shantytowns outside Nairobi, Kenya where 800,000 people are living without any sanitation system, or Korail, Bangladesh, where slum dwellers pay hundreds of times more per gallon of water from a trader than in .

"This will be a great challenge for Latin America, with the organization that you're seeing here also, to make sure you have time to catch up to this problem, which can otherwise lead to great health crisis," he said.

has led to conflicts over water, he said.

Major steps on water and sanitation would lead to a reduction of , improvement from and an overall reduction in poverty, Eliasson said. It would also help make gender relations more equal because women usually go after water and take care after sick children suffering from diarrhea and other illnesses.

Progress would also be reached on education as sick children often have to miss schooldays and parents are forced to take days off from their jobs to take care of them.

"If we do water and right, we can have a great improvement on other goals," Eliasson said. "That's the beauty of this, apart from taking care of a problem, which is undignified for us to have in today's world."