 On 13 April, rioting broke out at the army barracks in Zarqa, which contained the largest concentration of troops in the country, between mostly "hadari" (non-Bedouin) units loyal to Abu Nuwar and Bedouin-dominated units loyal to Hussein.Two main accounts emerged regarding this incident, known as the "Zarqa uprising" among other names, with one account having been advanced by Hussein and Western historiographers and the other by political dissidents and many in the Jordanian and Arab press.Pearson has said the "incident is steeped in mystery and persistent controversy", and Anderson likewise has written that "questions abound about whether this coup attempt originated with the military, led by Abu Nuwar and the Free Officers, or with the king and the Americans, who wanted an excuse to remove" the Arab nationalist movement "from Jordan's political scene".