Antonio Guterres, the U.N. high commissioner for refugees, said Wednesday Syria is spiraling towards a full-scale disaster with 1 million people in flight and millions more displaced internally.
"We are doing everything we can to help, but the international humanitarian response capacity is dangerously stretched," Guterres said.
Justine Greening, Britain's international development secretary, said the number of Syrian refugees is increasing at a rate far greater than originally feared, The Guardian reported.
The British government has urged its allies in the Persian Gulf to make good on promises of hundreds of millions of dollars in humanitarian aid for refugees.
Kuwait, Saudi Arabia and Qatar each pledged $300 million for the Syrian crisis at a record-breaking fundraising drive in January.
So far, the money has not been forthcoming.