Mexican presidential candidate Andres Manuel Lopez Obrador said Sunday that he would submit evidence of vote buying by his rival in the July 1 presidential election.

Obrador said he had "overwhelming and irrefutable proof" that his rival Enrique Pena Nieto bought millions of votes by spending more than six times the legal spending limit.

Obrador, candidate of the left-leaning Progressive Movement, said he would deliver the evidence to court next Wednesday, and the evidence of vote buying and other election irregularities would be displayed at Mexico City's central square next Sunday.

Official results show that Nieto won the election with 38.21 percent of the vote, compared to Obrador's 31.59 percent.

The electoral authorities have until Sept. 6 to ratify the election results and the new president is expected to take office on Dec. 1.

Nieto's Institutional Revolutionary Party denied Obrador's charges and accused him of financing his campaign with illegal funds.