MEXICO CITY -- (AP) -- Students participating in a five-month strike at Latin
 America's biggest university are demanding the resignation of the school's rector
 and negotiations without any prior conditions in order to settle the walkout.

 The demand was made in a statement read late Saturday at a huge rally in
 Mexico City's Tlatelolco Square to commemorate a massacre by the army in
 1968 that left approximately 300 people -- mostly students -- dead.

 Sunday marked 167 days the National Autonomous University, which has 268,00
 students, has been closed. The rectory building and the main campus have been
 closed and barricaded by the strikers and virtually all faculty buildings idled.

 The strike began as a protest to tuition increases and several reform measures.
 The school agreed to drop the tuition increase, but striking students continued
 pressing other demands, such as greater student participation in running the
 school.

 In Saturday's statement, the students insisted on the resignation of rector
 Francisco Barnes de Castro. Barnes de Castro made the decision to raise annual
 tuition from a symbolic 2 cents -- which it had been for nearly half a century -- to
 $145 to help defray mounting costs.

 Several attempts to mediate the dispute have failed so far.