Some 29,000 Somali children have died as famine rakes the Horn of Africa in the worst humanitarian crisis in a generation, says US officials, pleading for global partners to urgently step up aid. "Based on nutrition and mortality surveys... we estimate that more than 29,000 children under five nearly four percent of children have died in the last 90 days in southern Somalia," Nancy Lindborg, assistant administrator of the US Agency for International Development (USAID), told lawmakers. "It is the most severe humanitarian crisis in a generation, affecting food security for more than 12 million people across Somalia, Ethiopia, Kenya, Djibouti and surrounding areas," Democratic Senator Chris Coons said as he opened the hearing.