In 1962 the Syrian branch, until then a small group of intellectuals almost all of whom were Palestinian, reacted to the break-up of the United Arab Republic by establishing a mass-movement calling for immediate re-unification with Egypt. Membership quickly surged to several thousand, and the leadership participated in the first Ba'athist-led government established after the coup of 8 March 1963, though on a non-party basis. The Ba'ath Party and its allied officers almost immediately after the March coup began purging Nasserists from power, with dismissals, transfers and arrests during the Spring of 1963; the ANM was viewed as one of the most serious threats, because of its numerical force and ideological appeal to the Ba'athist constituency. The Ba'ath-ANM tensions culminated in a Nasserist coup attempt led by Jassem Alwan that was struck down in July, 1963, after which Nasserism and the ANM in particular was a spent force in Syria.