The Syrian crisis can be resolved only through political means, UN Secretary General Ban ki-Moon said on Tuesday.
Addressing the third Syrian donors conference here, Ban said the Syrian crisis would remain the "world's worst humanitarian disaster" if there was no political solution.
He added that more than $8.4 billion was required to provide relief to the over four million Syrian refugees.
The donors meet is being attended by representatives from 69 countries.
Ban said that last year's donor conference collected $2.4 billion but it was not enough to meet "our requirements".
He said that more than 220,000 Syrians had been killed in four years of civil war. The conflict had also led to regional instability.
UN High Commissioner for Refugees, Antonio Guterrs, said the Syrian crisis had reached a "tipping point".
If "we fail to provide adequate support for refugees and their hosts, we risk a further destabilization of the entire region".
The Emir of Kuwait, Sheikh Sabah al-Ahmad al-Sabah, opened the conference and pledged $500 million for the Syrian refugees. NGOs promised $507 million.
The Emir of Kuwait said his country and the international community would never abandon the Syrian people. He urged the the US to act fast to resolve the conflict -- politically.
"The international community ... feels their suffering and will not abandon them in their plight," he said, referring to the people of Syria.
He described the Syrian situation as the "biggest humanitarian catastrophe witnessed by humanity in our contemporary history".
The fighting had transformed entire streets and neighbourhoods of Syria into rubble and reduced buildings into ruins while people had become mere casualty figures.
The Syrian economy had suffered more than $200 billion in losses, unemployment stood at 57 percent while life expectancy rate had dropped to 55 years, the Emir said.
Poverty had risen, and the number of Syrian refugees outside the country stood at 3.9 million people, the biggest refugee society in the world, the Kuwaiti leader said.
At the same time, the crisis had created safe havens for terrorists who used the instability in Syria to carry out their "sinister plans", Sheikh al-Sabah said.
He praised Lebanon, Turkey, Jordan, Iraq and Egypt for hosting some 3.9 million Syrian refugees.
