The battle over the three-week-old high school teachers strike is getting angrier and more complicated, with parents now threatening to force a shutdown of the entire education system, and the National Labor Court giving the striking teachers until Sunday to respond to a petition demanding the resumption of teaching in grades 11 and 12. While Union of Local Authorities chairman Adi Eldar angrily quit as mediator between the government and the Secondary School Teachers Organization earlier this week, placing the ULA squarely in support of the labor court back-to-work orders, at least six mayors came out on the side of the union and against such injunctions on Thursday. The injunctions require the support of the local councils, technically the teachers' employers, to be implemented. The National Parents Association threatened to widen the scope of the strike, saying it will keep its children out of all schools, from pre-school to high school, and shut down the education system if the labor court orders the striking teachers back to work. Hundreds of parents across Israel demonstrated in support of the strike on Friday, Israel Radio reported. In Jerusalem, demonstrators blocked a central city street with the approval of police. In Holon and Bat Yam parents set out in a procession of cars to symbolize "the funeral" of the education system. The parents organization says it does not want teachers to be forced to teach, or to return to the situation that existed prior to the strike that started on October 10. It is unclear, though, to what extent the National Parents Association is capable of carrying out its threat, since many local parents organizations are organized in the separate Committee of Chairmen of Local Parents Organizations, which has publicly denounced the Secondary School Teachers Organization strike. The National Parents Association threat follows a ULA and Treasury petition to the court overnight Wednesday asking it to order teachers in grades 11 and 12 back into the classrooms to prevent the cancellation of winter matriculation exams scheduled in a few weeks. "This isn't meant to break the strike," ULA representatives said Thursday, "but to prevent harm to the children, who will miss their exams otherwise." The National Labor Court has given the SSTO until Sunday to respond to the petition. Eldar, who participated in four meetings with representatives of both sides, said "there [was] no choice but to approach a different forum." Eldar gave notice after the SSTO rejected a proposal by Finance Minister Ronnie Bar-On. The offer includes the signing of an agreed-upon collective wage agreement, a 5 percent increase in teachers' wages spread out over five years, and the promise of continuing discussions on educational reform plans in the coming months. "They think this is enough?" one SSTO representative asked The Jerusalem Post. "A 5% increase spread over years is the solution to this strike? It's the government's problem that it promised a different deal to the other union," she added, a reference to the collective wage agreement reached with the elementary school teachers union, the National Teachers Union. "That was a bad deal, and it won't fly with us." The Secondary School Teachers Organization is demanding an immediate 15% increase to salaries in exchange for a postponement of the reform process. "Unfortunately, long hours of talks ended with [SSTO head Ran Erez] responding in the negative to the proposal from the finance minister. Therefore, my role as a mediator has come to an end," Eldar said. Erez told Army Radio Thursday morning, "Actually, it is the Israeli government that doesn't want a better education for the children, doesn't want to ensure their futures. [The government] wants the teachers to be babysitters at school. "Our system is crumbling," continued Erez. "We must invest in our children's future, not in another F-15. The finance minister wants teachers to be satisfied with a 1.5% increase in salary per year. That is an increase of NIS 20 per teacher. It's spitting in our face." Meanwhile, the Senior Lecturers Union, representing university lecturers at public universities, announced Thursday it would expand its strike as it enters its third week on Sunday by boycotting most extracurricular activities on campus. "Since the strike began, there have been no serious negotiations" over wage increases the Lecturers Union is demanding to offset wage erosion since 2001. The Lecturers Union called on students to help "bring the strike to an end," and on Bar-On to intervene. Jerusalem Post staff contributed to this report.