Islamabad, Aug 21 : At least 20 people died after a devastating flash flood hit Khoshi district in Afghanistan's Logar province, officials said on Sunday. According to initial reports, half of the deceased were children, the provincial police said in a statement. Another 30 people were wounded and at least four were missing. As a result, more than 3,000 residential houses have been partially or completely damaged, dpa news agency reported quoting officials. Social media footage showed bodies of children as well as villages inundated by the flooding. "The situation is very worrying. People urgently need basic aid," police spokesman Ahmadullah Anas told dpa. Officials at the country's National Disaster Management Authority said they have been using helicopters to try to rescue those trapped by the flooding since Saturday evening and have set up an emergency camp. Afghanistan experiences seasonal flooding every year, damaging homes, agricultural land and public infrastructure. At least 32 people died in the country's northern province of Parwan last week after floodwaters rushed through several valleys. Flash floods usually catch people by surprise as there is no alarm system in the mountainous country. Decades of conflict, coupled with environmental degradation and insufficient investment in disaster risk reduction have contributed to the increasing vulnerability of Afghans to natural disasters, according to the United Nations. On average, natural disasters affect 200,000 people every year in the war-torn country. /IANS