Pakistans flood crisis has damaged more than 10,000 schools, affecting several million pupils and requiring massive investment in a nation struggling with literacy, the UN warned Wednesday. 'Five to six percent of all schools have been damaged by the floods. This means that between 1.5 to 2.5 million students have been affected, Umar Amal, an official with UNESCO, told a news conference. 'That number can rise and it will rise, he said, unable to estimate how much it would cost to repair the damaged infrastructure. The United Nations has issued a record $2 billion appeal to cope the disaster, which UN agencies say affected 21 million people and left 12 million in need of emergency food aid. Amal said more than 9,780 government schools were damaged, 2,700 fully and 7,000 partially. The number of private schools affected, a statistic he said was not yet available, would push the figure beyond 10,000, he said.