Late in 1928, as the Cristero War was raging in western Mexico, a new revolutionary faction led by General José Gonzalo Escobar drafted the "Plan of Hermosillo" and occupied the copper mining town of Cananea, Sonora, not far from the international border with the United States. Encouraged by their successes early on, they next decided to take control of Agua Prieta and Naco, both situated on the border with Arizona, knowing many of the locals were sympathetic to their cause and thinking the revenue generated by these two towns would be a good source of income for the revolution. From there, General Escobar intended to carry the war south and ultimately oust Emilio Portes Gil and take his place as president.