The United Nations said on Tuesday it will halt food aid to 400,000 Syrian refugees in Lebanon next month unless it receives urgent new funding.
The cash shortage is part of a wider financial shortfall that the organisation says is threatening its efforts to help nearly 1.3 million Syrian refugees and almost 4 million more people displaced inside Syria by the two-year conflict.
"The speed with which the crisis is deteriorating is much faster than the ability of the international community to finance the Syrian humanitarian needs," Panos Moumtzis, the UN refugee agency's regional coordinator for Syrian refugees said.
"We're afraid, if no more funds are made available urgently - and this is where we are at a breaking point - we will come to a point where we will have to start reducing aid, prioritising aid," he said in Geneva.
In Lebanon, where authorities and aid groups are struggling to cope with a growing wave of refugees already equivalent to 10 percent of the local population, the UN World Food Programme warned that it might be forced to cut back operations in May.
"In one month, and with the current funding, more than 400,000 Syrian refugees in Lebanon will no longer receive food assistance," WFP country operations head Etienne Labande said.
All refugees currently receive food when they register and then get monthly food coupons worth $27 a month, Labande said, but any interruption in that support could lead to unrest in a country where sectarian tensions have already been aggravated by the Syrian crisis.
"I am extremely concerned that without continued funding we will see increased tensions and further displacement in an already tense environment," Labande said.
The United Nations said in mid-February that around 70,000 people had been killed in the uprising against President Bashar al-Assad. Since then, violence monitors say more than 10,000 people have died. The fighting has also left whole districts of the Syria's historic cities in rubble.
The Beirut-based UN Economic and Social Commission for Western Asia estimates that 400,000 houses have been completely destroyed, 300,000 partially destroyed and a further half million suffered some kind of structural damage, so that one in three Syrian homes has been scarred by the war.
The United Nations says that so far only $400 million out of more than $1.5 billion pledged by international donors in late January to cover Syrian refugee needs for the first six months of this year has actually been committed.
It said last week the impact of the lack of funds would include a halt in 3.5 million litres of daily water deliveries to Jordan's Zaatari camp which houses more than 100,000 refugees, mostly children.
"There's tremendous pressure on the resources of these countries," Moumtzis said.
"The refugees are being hosted by some of the poorest of the poor communities in Lebanon. And this is where there is a huge fragility, Lebanon in particular but also in Jordan."
Moumtzis said he would be visiting the United States, Brussels and London to chase further donations but on the ground, aid workers said they were already feeling the pinch.
"It is a catastrophe. We are being asked to do more and more with less and less," UNHCR's Lebanon representative Ninette Kelley told reporters at the opening of a new registration centre for Syrian refugees in the southern coastal town of Tyre.
"We simply don't have the resources that we need in order to provide the assistance that is so desperately needed by the refugees and the help to the hosting community who so badly need it."