MEXICO CITY (Reuters) -Huge crowds filled Mexico City's main square on Sunday in support of the nation's electoral authority, accusing President Andres Manuel Lopez Obrador of trying to weaken the body ahead of a presidential election in June. The protests, one of several in recent years meant to "protect" the National Electoral Institute (INE), come after Lopez Obrador sent a sweeping package of constitutional reforms to Congress, which would include an overhaul of the INE. Organizers said 700,000 people turned out, which could mark one of the largest protests against Lopez Obrador as his administration comes to a close.