U.N. Secretary-General Ban Ki-moon urged the world to provide more aid to flood-ravaged Pakistan on Sunday as new torrents inundated villages. Pakistan's worst floods ever have killed about 1,500 people and damaged 7.9 million acres (3.2 million hectares) of cotton, sugar cane and wheat crops. The U.N. has appealed for an initial $460 million to provide relief, but only 20 percent has been given. U.N. chief Ban visited the country for talks with government leaders and to see the flood zone. «I am here to see what more needs to be done and to urge the world community to speed up the assistance to the Pakistan people,» he said. Waters five feet (1.5 meters) deep washed through Derra Allah Yar, a city of 300,000 people on the border of Sindh and Baluchistan provinces, said government official Salim Khoso. About 200,000 had fled the city. «We have to feed them, but we don't know how,» he was quoted as saying by the Associated Press. But in a televised address to the nation Saturday, Prime Minister Yousuf Raza Gilani said 20 million were now homeless. He did not elaborate, and it was unclear how many of those people were briefly forced to leave their homes and how many had lost their houses altogether. The United States has so far donated the most to the relief effort, at least $70 million, and has sent military helicopters to rescue stranded people and drop off food and water. Two additional U.S. Navy MH-53E Sea Dragon helicopters arrived in Pakistan on Saturday to support flood relief efforts, the U.S. State Department said. That brings to seven the total number of aircraft in Pakistan from the USS Peleliu, which is positioned in international waters in the Arabian Sea. In the northwest of the country, U.S. missiles killed 12 people Saturday in a Pakistani tribal region, the Associated Press reported.