The topographic surveyors and their aviation support pilots and crew served on field parties that endured sweltering heat in this Sub Saharan region of Africa. They also struggled to subsist in remote areas of the country that included jungles, deserts, dense bush, mountains and swamps that harbored deadly snakes, crocodiles, lions, leopards, hyenas, hippos, cape buffalo, elephants, wild dogs, dangerous bees and ants, aggressive tribes of baboons and sometimes hostile natives, not to mention any number of malignant diseases. In addition, these troops and their support personnel were frequently required to conduct their operations in active war zones along the Somalia and Sudan borders, where brutal wars and indiscriminate killing had been going on for years, and the area of the country that is now Eritrea, where the Eritrean Liberation Front was engaged in armed struggle with imperial Ethiopian forces as part of the Eritrean War of Independence. According to a country study commissioned by the U.S. Army, the Eritrean War of Independence began in 1961, and intensified in 1962 in response to Ethiopia dissolving the Eritrean-Ethiopian federation. By 1965, the Ethiopian Army devoted a division to fighting the ELF insurgency, including three battalions to guard cities in Eritrea, and a counterinsurgency battalion focused on direct action. The U.S. State Department also noted the effect of the increased insurgency in March of 1965, as the Ethiopian government requested an increase in security assistance aid due to the disruption caused by "Eritrean dissidence."