FILE - This June 7, 2015 file photo shows Jaime Rodriguez, known as "El Bronco," then an independent candidate for governor, on his horse, in Villa de Garcia, Mexico. Mexico's top electoral court has ordered on Tuesday, April 10, 2018, that Rodriguez be added to the ballot for the July 1, 2018, presidential election. (AP Photo/Hans-Maximo Musielik, File)

MEXICO CITY - Mexico's top electoral court ordered Tuesday that a fifth candidate be added to the presidential ballot, setting off a controversy less than three months before the July 1 national elections.

Jaime "El Bronco" Rodriguez, an independent candidate often seen astride a horse in the northern state of Nuevo Leon, was kept off the ballot last month by the electoral institute for not collecting enough legitimate signatures. He argued that the institute did not allow him a timely review and challenge for all of the rejected names.

The court ruled early Tuesday in a 4-3 vote that Rodriguez was not given a sufficient opportunity to contest signatures. It said he should be added to the ballot immediately since the official campaign period began nearly two weeks ago.

The decision was criticized by opponents and pundits for undermining the authority of the electoral institute and for placing a candidate on the ballot who the electoral institute had said provided fraudulent signatures.

Independent candidates were required to gather signatures from 866,000 people, or 1 per cent of the electorate on a national level, from 17 of Mexico's 31 states, plus the capital district.

In a statement, the court said Rodriguez successfully challenged nearly 63,000 signatures that had been rejected by the electoral institute and was only about 16,000 names short, which could be found upon further review.

Rodriguez is the second independent candidate in the race, joining Margarita Zavala, a lawyer and former lawmaker and first lady. He won the governorship of Nuevo Leon as an independent in 2015.

In an interview with ForoTV, Rodriguez said the criticism of the court's decision illustrates the political establishment's fear of his candidacy. Rather than attack him, he said, they should be trying to win voters' support.

Rodriguez said he wants to end the dominance of Mexico's national political parties, so "they're not going to speak well of me."

Zavala, in an interview with Radio Formula, said she disagreed with the court's decision and worried that applying the rules differently to some candidates would generate uncertainty in the electoral process. She forged her own independent candidacy after splitting from the National Action Party, which carried her husband, Felipe Calderon, to the presidency in 2006.

Leftist Andres Manuel Lopez Obrador of the Morena party remains the election front-runner.

It is not clear which candidate is most likely to lose votes to Rodriguez.

News from © The Associated Press, 2018