Syria's war and the refugee crisis it triggered are at real risk of exploding across the Middle East, the UN refugee agency said on Friday, on the second anniversary of the outbreak of the conflict.UN High Commissioner for Refugees Antonio Guterres also urged the world to strive to end the conflict and to step up humanitarian aid, calling it a "morale obligation" and "essential to preserve global peace and global security.""I believe that if the Syrian conflict goes on and on and on, there is a real risk of an explosion in the Middle East, and then there will be no way to cope with the challenge from the humanitarian, political and security perspective," said Guterres.The United Nations says more than 1.1 million Syrians have fled mostly to Jordan, Iraq, Lebanon and Turkey, and some four million others have been displaced inside their war-torn country.Guterres — in Lebanon on the last leg of a regional tour that also took him to Jordan and Turkey — raised the alarm over the potential security impact the refugee crisis could have on Syria's neighbours."The Syrian crisis is not just another crisis, and what we are dealing with now is that the Syrian crisis is a tipping point," he told reporters."Things get much worse before they get better. Not only do they get much worse in Syria, but they can have a very, very big impact on the countries around."Citing what he said was a financing gap of $700 million (535 million euros), Guterres also called on governments to unlock extraordinary funds to support the refugees and the countries that host them."There is no way a gap of this magnitude can be filled with current humanitarian budgets," he said.Humanitarian organisations have only received 30 per cent of the funds required to cover basic needs."I think it is in the interest of everybody to solve the conflict, to have a political solution to the conflict, but it is also in the interest of everybody to fully address the humanitarian needs."Lebanon has already seen a spillover of the conflict in recent months, with frequent clashes in the northern and eastern areas of the country.Syrian troops have also fired shells over the border, while the Damascus regime has accused Lebanon of allowing Sunni fighters to cross illegally into Syria to join the rebels.Lebanon was dominated politically and militarily for 30 years by Damascus.Today it is sharply divided over the conflict, with Shiite movement Hizbollah and its allies backing the regime of President Bashar Al Assad and the Sunni-led March 14 movement supporting the rebels.Experts have frequently warned of a spillover of Syria's conflict into Lebanon, which the UN says currently hosts at least 354,000 Syrians who fled the conflict.