Oxfam's Syria Response Campaign Manager, Claire Seaward, based in Jordan, said:
"We are appalled that this landmark has been reached today.
"Enough is enough. A generation of Syrians is paying too high a price in this conflict. They have been seriously let down by the international community, which has failed to prioritise a political solution to the conflict. That must change. World leaders - especially President Obama and President Putin - must ensure the long-promised peace talks take place as soon as possible.
"Every day more refugees cross the borders into neighbouring countries - often traumatised and in need of the basics: food, water and shelter. But the humanitarian response to the crisis is stretched to the limit. Donor countries must continue to dig deep and donate to the UN appeals that are still only 41 per cent funded."