THE UN in Pakistan has described the humanitarian situation caused by the flood disaster as critical. As floodwaters continue to travel south through the country, tens of thousands of people are being displaced each day, BBC reported on Monday. A senior United Nations official has called on the global community to urgently step up its response to the floods that have struck Pakistan. Louis-George Arsenault, director of emergency operations for Unicef in New York, described the lack of support as quite extraordinary, warning that the humanitarian crisis was the largest in decades. Arsenault spoke as the International Monetary Fund was due to start talks with Pakistani officials in Washington. The talks on Monday will allow the IMF to assess how best to help. It says the floods that have struck Pakistan pose a massive economic challenge and it will review the countrys budget and financial prospects. The UN says it has raised close to 70pc of the $460m it called for in its emergency appeal for the people affected by the worst floods in Pakistan. Some $54m are in uncommitted pledges, and $263m are resources available now. As officials prepared for the IMF meetings, Arsenault, of the UN childrens fund, said: One of the major challenges that we have which is quite extraordinary is the lack of level of support from the international community. Right now, our level of needs in terms of funding is huge compared to what weve been receiving, even though this is the largest, by far, humanitarian crisis weve seen in decades. Meanwhile, the World Health Organisation says diseases are spreading in affected areas. Experts warn of a second wave of deaths from water-borne diseases such as cholera unless flood victims have access to supplies of fresh drinking water. The floods began last month in Pakistans northwest after heavy monsoon rains and have since swept south.