In this Sunday, Dec. 15, 2013 citizen journalism image provided by Aleppo Media Center, AMC, which has been authenticated based on its contents and other AP reporting, Syrians inspect the rubble of damaged buildings following a Syrian government airstrike in Aleppo, Syria. The Britain based Syrian Observatory for Human Rights said Monday that dozens of children were among scores killed in airstrikes on several opposition areas a day earlier. AP Photo/Aleppo Media Center AMC In this Sunday, Dec. 15, 2013 citizen journalism image provided by Aleppo Media Center, AMC, which has been authenticated based on its contents and other AP reporting, a Syrian man cries while holding the body of child who was killed following a Syrian government airstrike in Aleppo, Syria. AP Photo/Aleppo Media Center, AMC In this Sunday, Dec. 15, 2013 citizen journalism image provided by Aleppo Media Center, AMC, which has been authenticated based on its contents and other AP reporting, Syrians gather around damaged buildings while others try to extinguish fires following a Syrian government airstrike in Aleppo, Syria. In this Sunday, Dec. 15, 2013 citizen journalism image provided by Aleppo Media Center AMC, which has been authenticated based on its contents and other AP reporting, Syrians inspect damages buildings following a Syrian government airstrike in Aleppo, Syria. The Britain based Syrian Observatory for Human Rights said Monday that dozens of children were among the scores killed in airstrikes on several opposition areas a day earlier. This Sunday, Dec. 15, 2013 citizen journalism image provided by Aleppo Media Center AMC, which has been authenticated based on its contents and other AP reporting, shows flames rising from burning vehicles following a Syrian government airstrike in Aleppo, Syria. BEIRUT (AP) - The exodus of millions of people from Syria in one of the largest refugee flights in decades is pushing neighboring countries to a breaking point, and thousands of lives are threatened with the onset of a bitter winter. The crisis prompted a record appeal by the United Nations on Monday for $6.5 billion to help displaced Syrians and their host countries, with hundreds of thousands more refugees expected as the civil war rages. With less than a month to go before internationally brokered peace talks by Syria's warring sides are to begin, the U.N. chief demanded a cease-fire for the discussions to have any chance in succeeding. "We must have cessation of hostilities before we begin political dialogue on Syria in Geneva," Secretary General Ban Ki-moon told reporters in New York. But if anything, the violence in Syria, which activists say has already claimed more than 120,000 lives, appears to be spiraling. Opposition groups said at least 76 people were killed in a series of airstrikes targeting the northern city of Aleppo on Sunday. They said government aircraft took to the skies again Monday, hitting opposition-held areas in the country's north and south. Amateur videos posted online showed the aftermath of Sunday's airstrikes: leveled buildings, rubble-strewn streets and the smoldering wreckage of vehicles. The images corresponded to Associated Press reporting on the strikes. The conflict in Syria, now in its third year, has defied all attempts at peace. In addition to the staggering death toll, millions of people have been displaced from their homes, most now scattered in refugee camps and informal settlements across Lebanon, Jordan and Turkey. A biting cold spell marking the beginning of winter has added another layer of misery to their grim existence. The situation in Syria has "deteriorated beyond all imagination," Ban said. In Geneva, the U.N. appealed to donors for $6.5 billion to help support the nearly 9 million uprooted Syrians, the largest-ever appeal for a single crisis. Antonio Guterres, the U.N. High Commissioner for Refugees, said the Syrian civil war has helped push the number of people worldwide who fled conflict in their homelands to more than 2 million this year alone - the highest since 1994, when people fled genocide in Rwanda and bloodshed in the former Yugoslavia. He described the nearly three-year conflict in Syria as a "mega-crisis" with regional dimensions, one that is "probably the most dangerous for global peace and security since World War II." Experts say what makes the Syrian conflict particularly challenging is the consistent, steady flow of refugees, overwhelming aid efforts and making it impossible to predict long-term needs. Peter Kessler, UNHCR senior regional spokesman, said at least 120,000 Syrians seek shelter in Lebanon, Jordan, Turkey and Iraq every month. The needs are enormous and the host countries cannot meet them on their own. They need help," Kessler told the AP by phone from the Lebanese border town of Arsal, where the population has skyrocketed. Lebanon has been particularly hard hit, because the government kept the borders open and no formal refugee camps have been established. Over the past few weeks, 21,000 Syrians have fled to the Arsal area as fighting intensified in Syria's neighboring Qalamoun region, Kessler said. Charity groups and non-governmental organizations this past week scrambled to cope with the fallout from a snowstorm, handing out blankets, mattresses, kerosene heaters, winter clothes, plastic tarps and fuel coupons. The storm hit Lebanon, the Palestinian territories, Turkey, Israel and even the deserts of Egypt with rare snow and rain. Some 1.4 million Syrians now live in Lebanon, which had a population of 4.5 million before the refugee crisis. Guterres said Lebanon is now close to reaching the population it was expected to have by the year 2050. In Jordan, a plastic-tent Syrian refugee encampment has become the country's fourth largest city. Some 120,000 Syrians live in the Zaatari camp, while the rest live in existing Jordanian communities. Many residents complain that the newcomers have exhausted their meager resources, like water, health care and education. The U.N. Security Council, deeply divided over the civil war, has been unable to ensure better access to humanitarian assistance inside Syria itself. The U.N. food agency said it is expanding its emergency operation to provide food. Recent assessments by the World Food Program show that almost half the population inside Syria is experiencing food shortages and that more than 6 million people urgently need food to survive because of soaring prices. In addition to the 2.3 million Syrians who have fled the country over the course of the war, there are 6.5 internally displaced people. In the suburb of Jaramana on the outskirts of Damascus, Syrian children lined up Monday at a center to get hot food provided by the Syrian Red Crescent and the World Food Program. The youngsters held up little pails for servings of a dish of rice, lentils and pasta, seasoned with oil and salt. "It has been very, very difficult with the bad weather in the whole of the Middle East," WFP spokeswoman Jane Howard told the AP in Italy. We've started to distribute fuel so they can cook their food assistance and also heat up their shelters because we are really quite worried that they were not ready for this kind of bad weather. At the United Nations on Monday, Russia lashed out at the U.S. and its allies on the Security Council over who is to blame for chemical weapons attacks in Syria this year. Russian Ambassador Vitaly Churkin told the council that the dramatic Aug. 21 attack that led to Syria's agreeing to give up its chemical stockpile was "staged" and a "large-scale provocation." Churkin compared it to the "manipulation of public opinion" that led up to the U.S. invasion of Iraq. He read reporters the statement he read to council members. The current council president, French Ambassador Gerard Araud, told reporters only that members had an "acrimonious exchange." A U.N. inspection team's final report last week said chemical weapons probably were used in Syria several times. The team did not say who was responsible. Heilprin reported from Geneva. Associated Press writers Zeina Karam and Ryan Lucas in Beirut, Edith M. Lederer at the United Nations and Nicole Winfield in Rome contributed reporting.