UNHCR: Two million Syrians are refugeesListen / The number of Syrian refugees has passed the two million mark, according to the UN refugee agency (UNHCR).
Inside Syria, a further 4.25 million people have been internally displaced.
UNHCR says about 5,000 to 6,000 Syrian women, children and men are fleeing into neighbouring countries every day, often with nothing more than the clothes on their backs.
United Nations High Commissioner for Refugees Antonio Guterres says the tide of human suffering unleashed by the Syrian conflict has catastrophic implications, adding that if the situation continues to deteriorate, the number of refugees will only grow and some neighbouring countries could be brought to the point of collapse.
Mr Guterres says countries hosting Syrian refugees urgently need massive international support to help them deal with the crisis.
"To preserve the stability of those countries in this extremely difficult situation is absolutely essential. The war is already spilling over into Lebanon and into Iraq and the risks of an explosion in the Middle East are growing by the day. Without this kind of massive support to countries like Lebanon, Jordan, but also Iraq's Kurdistan region and Turkey; without that massive support, it will be much more difficult to preserve the stability of these countries and to avoid the spillover of this conflict. We have a planning figure of 3.5 million refugees to the end of the year, which means we are prepared for different forms of escalation. We have had several. We are prepared for things to get worse before they get better."
UNHCR says the Syrian humanitarian response plan is worryingly underfunded, with only 47 per cent of funds required to meet basic refugee needs received so far.
Patrick Maigua, United Nations Radio, Geneva.