Sana'a: Yemen's embattled President Ali Abdullah Saleh on Friday gave a cool response to a Gulf plan for him to quit, even as massive crowds returned to the streets to demand his immediate ouster. While tens of thousands of anti- and pro-Saleh demonstrators packed two different locations in Sana'a, suspected Al-Qaeda militants and tribesmen gunned down 13 soldiers in separate attacks in Marib province, eastern Yemen. “We stress that we will hold on to the constitutional legitimacy, in loyalty to our people, as we categorically reject the attempted coups on freedom, democracy, and political pluralism,” Saleh told regime supporters in Sana'a. In a cool reaction to a Gulf plan for him to step down within 30 days, Saleh said he welcomed the initiative but only “within the framework of the constitution,” signalling he could try to serve out his term until 2013. As on past Fridays, a huge rival rally by anti-regime protesters massed a few kilometers away kept up the pressure for Saleh's immediate departure on what they branded a “Last Chance Friday.” In the latest version of the Gulf Cooperation Council (GCC) initiative, the president would submit his resignation to parliament within 30 days, with a presidential vote to be held within two months. A motor of the revolt, the “Peaceful Revolt Youth,” Friday renewed its rejection of the GCC initiative. The cause was that the proposal does not call for Saleh's immediate departure and grants immunity from prosecution to the president, family and aides, “who are all killers,” it said in a statement. The group called for a nationwide general strike Saturday. Meanwhile, Yemeni authorities arrested dozens of soldiers and military officers Friday for joining anti-government protesters, a military official said, in an attempt to halt defections chipping away at a critical line of defense for the embattled president. A brutal crackdown on more than two months of protests — including deadly sniper attacks — triggered a wave of key figures to abandon Saleh, who is clinging to power after 32 years ruling over the fragile country on Arabia's southern edge. Other than military figures, the defectors include ruling party members, lawmakers, Cabinet ministers, top diplomats and even Saleh's own tribe. In comments to supporters Friday, Saleh ridiculed them and other protesters as “cowards” and “renegades.” A military official said Friday's arrests targeted several senior officers and dozens of soldiers. The arrests were carried out after a demonstration against the president by dozens of soldiers and airmen at the Anad air base in the southern Lahj province Tuesday, said the official, a colonel who spoke on condition of anonymity.