A helicopter crash in southwestern Nigeria has left three people, including the pilot, dead, an emergency official said Saturday after a six-hour search in a wooded area to locate the wreckage. The private helicopter crashed Friday outside Ife-Odan in Osun state in a mountaineous area, said Yushau Shuaib, spokesman for the national emergency management agency (NEMA). He told AFP that three people aboard the OAS helicopter -- the pilot and two women -- died. Full details of the crash remained unclear, including the cause, he said. \"The crash happened in an extremely difficult montaineous area, difficult to access. No vehicle or motorcycle can access the area. It is just now that our officers are bringing down the three corpses,\" he said. The helicopter, travelling from Lagos to the north-central city of Ilorin, crashed on a hilltop more than 1,000 feet above sea level, he said. He said that NEMA suspects poor visibility as the cause of the accident. \"NEMA director general (Mohammed) Sani-Sidi said they would work with other agencies to determine what happened to the emergency locator beacon which could have sent a distress signal to NEMA MCC (Mission Control Centre),\" Shuaib added.