MEXICO CITY – Thousands marched through Mexico City’s center on Sunday to protest what they called the “imposition” of the old ruling party’s candidate as the country’s new president.

Protesters carried signs accusing presumed President-elect Enrique Pena Nieto of electoral fraud and Mexico television giant Televisa of being a “factory of lies.” Opponents say Nieto’s party, the Institutional Revolutionary Party, won the July 1 election through vote-buying and overspending, including paying major media outlets such as Televisa for favorable coverage.

“Mexico didn’t vote for fraud. Mexico wants a country that is honest and democratic,” said marcher Marlem Munoz, 26, who studies dentistry at Mexico’s National Autonomous University. “What happened in the elections was a total mockery directed at the Mexican people.”

The PRI has vehemently denied the charges and on Friday accused losing leftist candidate Andres Manuel Lopez Obrador of trying to “disqualify the entire electoral process with lies.” Televisa also has denied charges of being paid for positive coverage.

Mexico City authorities did not immediately release an official crowd estimate, but the march appeared to draw far fewer people than similar protests before the election that had as many as 90,000 participants. A July 7 march drew 50,000. The events have attracted people from a new student movement, “I Am 132,” and leftist groups supporting Lopez Obrador.

Nieto, 46, won by 6.6 percentage points, bringing the PRI back to power after 12 years in opposition. The party had previously ruled Mexico for 71 consecutive years with what critics say was the help of corruption, patronage and vote fraud.