Iraq showed reluctance in fulfilling existing agreements with Iran—especially after Egyptian President Gamal Abdel Nasser's death in 1970 and the Iraqi Ba'ath Party's rise which took power in a 1968 coup, leading Iraq to take on the self-appointed role of "leader of the Arab world". At the same time, by the late 1960s, the build-up of Iranian power under Shah Mohammad Reza Pahlavi, who had gone on a military spending spree, led Iran to take a more assertive stance in the region.