and modernize their military but at a stagnate rate, this despite the fact the region was regularly at war. In 1969, South Yemeni forces attacked the Kingdom along the border but were swiftly defeated by Royal and allied forces. When the Yom-Kippur War broke out in 1973, Saudi Arabia used "Oil as a weapon", to aid the Arab cause; this strategy significantly influenced world opinion against Israel though to what extent is remains unclear. Following these successes, the Saudis would pursue only limited increased support for their armed forces in the wake of the Grand Mosque Seizure in 1979. In the 1980s Saudi Arabia became a major source of financial but not military assistance, for the Mujahideen in Afghanistan, and the regime of Saddam Hussein in its war against Revolutionary Iran. The 1991 Gulf War saw the greatest threat to the Kingdom in modern history and the largest deployment of Saudi Armed Forces in history, with all levels of the Saudi military actively participating as part of the U.N. coalition against Iraq. In 1987, members of the air force, army, and navy used to be mainly recruits from groups of people without a strong identity from the Nejd tribal system and people from urban areas. King Abdullah increasingly moved towards comprehensive military reform following what he considered a failed response by Saudi forces to Houthi incursions in 2009. In the early 2010s, after almost 20 years of relatively modest increases in military spending, the Saudi government embarked an unprecedented expansion of the Kingdom's armed forces. This shift in policy was spear-headed primarily by Crown Prince Mohammed bin Salman, who took over as Defense Minister in 2015. It is believed the continued high level expansion of the Saudi Armed Forces was a response to not only short term threats (including incursions by Yemeni rebels and the rise of ISIS) but long term regional strategic concerns, namely the increasing strength of Iran and the uncertain future of America's role in the region. In 2019, the government of Saudi Arabia stated that women can start working in the military. In the past they could only work in police. Military services The armed forces are mainly the responsibility of the Ministry of Defense and Aviation, which also oversees the construction of civilian airports as well as military bases, and meteorology departments. Crown Prince Sultan bin Abdulaziz was Saudi Arabia's Minister of Defense and Aviation