The 1950s became known as the Arab Cold War, due to the conflict between states led by Nasserist Egypt and traditionalist kingdoms led by Saudi Arabia. Egypt and Syria formed the United Arab Republic (UAR) on 1 February 1958, with the Republic's presidency occupied by Nasser. As a counterweight, Hussein and his cousin, King Faisal II of Hashemite Iraq, established the Arab Federation on 14 February 1958 in an Amman ceremony. The two rival entities launched propaganda wars against each other through their radio broadcasts. Jordanian and Syrian forces clashed in March along the border. UAR-inspired conspiracies started to emerge against the Hashemite federation. An officer in Jordan was arrested for plotting to assassinate Hussein. It also emerged in Jordan that the UAR was planning to overthrow both Hashemite monarchies in July 1958. Jordan reacted by arresting 40 suspected army officers, and Hussein called in Iraqi army chief of staff Rafiq Aref to brief him on the exposed plot. Aref replied, "You look after yourselves. Iraq is a very stable country, unlike Jordan. If there are any worries it is Jordan that should be worried." Although Faisal and Hussein enjoyed a very close relationship, Faisal's Iraqi entourage looked down on Jordan; Hussein attributed this attitude to Iraqi crown prince 'Abd al-Ilah's influence.