Actress and UN ambassador Angelina Jolie has released a video asking for help on behalf of people affected by the floods in Pakistan.
Ms Jolie said: "This is not just a humanitarian crisis. It is an economic and social catastrophe.
"The UN is on the ground. The more support we can give the greater number of tents, food, clean water and medicine will get to the people in need."
The appeal comes after thousands of people streamed back to the historic southern city of after new levees were hastily built from clay and stone to hold back flood waters.
But thousands who fled the waters that inundated neighbouring towns complained about the shortage of food and water as they camped in a vast Muslim graveyard on a hill near Thatta city.
The floods began over a month ago in the north west after extremely heavy monsoon rains and surged south along the Indus River.