The United Nations has suspended a food programme for more than 1.7 million Syrian refugees in five countries because donors are not fulfilling their commitments.
Saying the suspension will be lifted immediately if new funding arrives, the World Food Programme (WFP) warned of “devastating” consequences for families over the winter.
The executive director, Ertharin Cousin, said: “A suspension of WFP food assistance will endanger the health and safety of these refugees and will potentially cause further tensions, instability and insecurity in the neighbouring host countries.
“The suspension of WFP food assistance will be disastrous for many already suffering families.”
The programme allocates vouchers to allow Syrian refugees in Jordan, Lebanon, Turkey, Iraq and Egypt to buy food in local shops.
A spokesperson for the WFP said that many refugees are unprepared for a harsh winter, especially in Lebanon and Jordan, where many children are reportedly barefoot and without proper clothing, living in bad hygiene conditions in mud-drenched tents.
Calling on donors to honour their pledges, Ms Cousin said the agency needed $64 million (£40 million) “immediately” continue the food programme this month.
According to the UN’s refugee agency (UNHCR), there are more than 3.2 million Syrian refugees outside of the country and 7.6 million people displaced within the country.
Many are in temporary camps but of those resettled abroad, figures by Statista shows that Germany has housed the most refugees.
The country has pledged to place 20,000 people, compared to 5,600 for Australia in second place.
Britain was criticised for refusing to sign the UN refugee agency’s resettlement programme.
The WFP estimates that $800 million (£510 million) of its vouchers have been used by Syrian refugees since start of the continuing civil war in 2011.
The UN High Commissioner for Refugees, António Guterres, said the timing of the crisis could not be worse.
“Winter is already an extremely difficult period for Syrian refugees, but the suspension of food assistance at this critical juncture is going to be devastating,” he said.
In pictures: Global refugee crisis
In pictures: Global refugee crisis
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Yemeni refugees carry water to their tent at the Mazraq internally displaced people's camp in the northwestern province of Hajja
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A displaced man from Yemen's Saada province amid UNHCR tents at a camp set up by the United Nations High Commissioner for Refugees in Mazraq in Yemen's Hajja region, 360 kms northwest of Sanaa
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Yemeni refugees queue to get food aid at the Marzaq internally displaced people's camp in Harad in the northwestern province of Hajjah
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Displaced Yemenis from al-Jaachan Al-Ansin, a village in the province of Ibb, some 200km South-East of Sanaa, stand next to their tents in a makeshift refugee camp in Sanaa
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Yemeni refugees walk to a refugee camp in the southern Saudi province of Jizan after crossing the border from Yemen into Saudi Arabia
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Syrian refugees arrive in Turkey at the Cilvegozu crossing gate of Reyhanli, in Hatay. The number of people driven from their homes by conflict and crisis has topped 50 million for the first time since World War II, with Syrians hardest hit, the UN refugee agency (UNCHR) said, in an annual report released on World Refugee Day
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Syrian refugees walking among tents at Karkamis' refugee camp near the town of Gaziantep, south of Turkey
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South Sudanese refugees waiting for food in the Kule refugee camp near the Pagak Border Entry point in the Gambella Region, Ethiopia
9/41 African refugees
African refugees live homelessly at a temporary shelter beside a road on World Refugee Day in Sana'a, Yemen. The number of African refugees who have come to Yemen during the past few years has reached 750,000, most of them are Somalis
10/41 Iraqi refugees
An Iraqi refugee girl from Mosul stands outside her family's tent at Khazir refugee camp outside Irbil, 217 miles (350 kilometers) north of Baghdad, Iraq. The militants' capture of Iraq's cities of Mosul and Tikrit makes their dream of a new Islamic state look more realistic. It already controlled a swath of eastern Syria along the Euphrates River, with a spottier presence extending further west nearly to Aleppo, Syria's largest city. In Raqqa, the biggest city it holds in Syria, it imposes taxes, rebuilds bridges and enforces the law - its strict version of Shariah
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Refugees queue to register at a temporary camp in northern Iraq
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A young Syrian refugee stands near jerry cans used to collect water at Al-Zaatri refugee camp in the Jordanian city of Mafraq, near the border with Syria. The United Nations hopes that political talks between the warring sides in Syria will clinch local ceasefires to allow vital food and medicines to reach millions of civilians
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A child refugee from the northern province of Raqqa in Syria, reacts from the cold weather in a Syrian refugee camp beside the Lebanese border town of Arsal, in eastern Bekaa Valley
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Boys help their father remove snow in front of their tent in the Azaz refugee camp
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A Syrian refugee family from Aleppo crosses the Bosphorus from Uskudar to the European side of Istanbul
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A child refugee stands next to a home constructed using a billboard in the settlement of Qab Elias in the Bekaa Valley, Lebanon
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Refugee baby Rim in the settlement of Qab Elias in the Bekaa Valley, Lebanon
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Refugees arriving at a camp near Bossangoa, 190 miles north of Bangui, the capital. Forty-one thousand people fled their homes following mass executions in the area
Juan Carlos Tomasi/Médecins Sans Frontières/Doctors Without Borders
19/41 Syrian refugees
Representatives of Syrian President Bashar al-Assad, a deeply divided opposition, world powers and regional bodies started a long-delayed peace conference aimed at bringing an end to a nearly three-year civil war
20/41 Iraqi refugees
A women and a girl wash at a tap at a temporary displacement camp set up next to a Kurdish checkpoint in Kalak. Thousands of people have fled Iraq's second city of Mosul after it was overrun by Isis (Islamic State of Iraq and Syria) militants. Many have been temporarily housed at various IDP (internally displaced persons) camps around the region including the area close to Erbil, as they hope to enter the safety of the nearby Kurdish region
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Families arrive at a Kurdish checkpoint next to a temporary displacement camp in Kalak
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An Iraqi refugee girl from Mosul stands outside her family's tent at Khazir refugee camp outside Irbil, 217 miles (350 kilometers) north of Baghdad, Iraq. Days after Iraq's second-largest city fell to Isis fighters, some Iraqis are already returning to Mosul, lured back by insurgents offering cheap gas and food, restoring power and water and removing traffic barricades
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A girl, who fled from the violence in Mosul, carries a case of water at a camp on the outskirts of Arbil in Iraq's Kurdistan region
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A displaced Iraqi woman washes her family's laundry as the children shower outside their tent at a temporary camp set up to shelter civilians fleeing violence in Iraq's northern Nineveh province in Aski kalak, 40 kms west of the Kurdish autonomous region's capital Arbil
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Iraqi refugees from Mosul arrive at Khazir refugee camp outside Irbil, 217 miles (350 kilometers) north of Baghdad
26/41 Sudanese refugees
The international Red Cross said that the road from Bor to the nearby Awerial area 'is lined with thousands of people' waiting for boats so they could cross the Nile River and that the gathering of displaced 'is the largest single identified concentration of displaced people in the country so far'
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People unload the few belongings at Minkammen, that they were able to bring with them to the camps
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Thousands of exhausted civilians are crowding into the fishing village of Minkammen, a once-tiny riverbank settlement of a few thatch huts 25 kilometres (20 miles) southwest of Bor
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Many people had spent days hiding out in the bush outside Bor as gunmen battled for control of the town, which has exchanged hands three times in the conflict, and remains in rebel control
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A young boy pulls his suitcase of belongings as he walks to find a place to rest after getting off a river barge from Bor
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A displaced family camp under a tree providing partial shade from the midday sun
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A boy carries a fish, caught from the nearby Nile river, in a cardboard box on his head back to his relatives to eat
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A mother and her baby, one of the few to have a mosquito net, wake up in the morning after sleeping in the open
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Four-month old Haida Majzub was born in the Ajuong Thok refugee camp inside South Sudan. The camp, in northern Unity State, hosts thousands of refugees from the Nuba Mountains, located across the nearby border with Sudan
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A girl fills a container with muddy water in the Ajuong Thok Refugee Camp
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The clashes in South Sudan began when uniformed personnel opened fire at a meeting of the governing party, the Sudan People's Liberation Movement
37/41 Myanmar refugees
45 year old Dilbhar looks towards the camera as she stands in the Shamalapur Rohingya refugee settlement in Chittagong district. She escaped to Bangladesh from the Bodchara village in the Mondu district of Myanmar
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32 year old Mahada Khatum, 5 year old Hasan Sharif, and 9 year old Umma Kulsum sit outside their home in the Shamalapur Rohingya refugee settlement in Chittagong district. The family escaped violence and discrimination from the Zomgara Baharchara village in the Meherulla district of Myanmar
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Hamid and his daughter Rajama sit inside their home in the Shamalapur Rohingya refugee settlement in Chittagong district. They fled to Bangladesh from the Dhuachopara village in the Rachidhong district of Myanmar
40/41 Afghan refugees
Afghan children wait for relief supplies from the Muslim Hands United For The Needy during an aid distribution at a refugee camp on the outskirts of Kabul
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Afghan people carry relief supplies received from the Muslim Hands United For The Needy during an aid distribution at a refugee camp on the outskirts of Kabul
“It will impact tens of thousands of the most vulnerable refugee families who are almost entirely dependent on international aid. I urgently appeal to the international community – support WFP now, don’t let refugees go hungry.”
The WFP has supplied food and vouchers to millions of displaced people inside Syria and up to 1.8 million refugees in neighbouring countries over the last three years.