"The (UN) Office for the Coordination of Humanitarian Affairs (OCHA) says that the flash floods in Pakistan's Sindh, Punjab and Balochistan provinces in early last month had triggered a humanitarian crisis which continues to unfold," UN spokesman Martin Nesirky told reporters here Friday. "Nearly 270,000 people have been displaced, with nearly half a million houses having been damaged and huge amounts of crops lost, " Nesirky said at a daily news briefing here. Monsoon rains and flooding in Pakistan have killed at least 400 people and injured nearly 3,000 others, during this year's rainy season, reports said in late September. In southeastern Pakistan's Sindh province, 239 people have been killed by rising flood-waters. Massive monsoon rains that have swept across the country have caused many rivers and streams to overflow. A total of 5 million people are thought to have been affected in some way by the floods. In recent years, Pakistan has struggled to cope with the annual rainfall and resulting floods. It needs international help to provide people with food, water and housing, said the reports. "The Office has established a humanitarian coordination center for operations in Sindh province and has deployed staff to support the response in Balochistan," Nesirky said. The UN Children's Fund (UNICEF) estimates that 3,200 schools have been damaged, disrupting schooling for half a million children, he said. "UNICEF says that it is reaching tens of thousands of children and families with safe water, hygiene supplies, malnutrition screening and treatment."