MEXICO CITY, Nov 13 (Reuters) - Tens of thousands took to the streets in Mexico on Sunday to protest President Andres Manuel Lopez Obrador's plan to overhaul the country's electoral commission INE in what they fear would concentrate power in the hands of the government.Lopez Obrador, who put the plan forward in April, has long criticized the country's electoral authorities, including accusing them of helping to engineer his defeats when he ran for the presidency in 2006 and 2012.Protesters in Mexico City, many holding placards and banners or wearing t-shirts with slogans "defending the INE", started at the Angel of Independence monument.Organizers put the number at hundreds of thousands but some political allies of Lopez Obrador gave far lower estimates."I hope that many young people - and even those who are normally not interested in politics - will attend, that they will value our institutions, and will defend what our parents and grandparents built to mature politically.""