MEXICO CITY (Reuters) - The trailing pack of candidates in Mexico’s July 1 presidential election on Sunday launched repeated attacks on the leftist front-runner in a first televised debate, putting him on the defensive without luring him out into an open verbal brawl.

Leftist front-runner Andres Manuel Lopez Obrador of the National Regeneration Movement (MORENA) gestures while leaving the Palacio de Mineria after the first presidential debate in Mexico City, Mexico April 22, 2018. REUTERS/Henry Romero

Race leader Andres Manuel Lopez Obrador came under sustained fire from his nearest challenger Ricardo Anaya, who sold himself as the only viable alternative for the presidency, calling out his rival for evading questions and accusing him of hypocrisy.

Buoyed by massive discontent with the ruling Institutional Revolutionary Party (PRI) over corruption, record levels of violence and sluggish growth, Lopez Obrador has pledged to clean up politics, reduce lawlessness and tackle inequality.

Many of the attacks on him focused on a proposal he floated to explore an amnesty for criminals to pacify the country. Last year Mexico suffered its worst murder tally on record under President Enrique Pena Nieto, who cannot run for office again.

“Proposing a pardon for criminals is madness, and would lead to an immense amount of violence in the country,” Anaya said.

Lopez Obrador rarely responded directly to the criticism, but about a quarter of the way into the debate focusing on security, corruption and democracy, his patience wore thin.

“Obviously everyone’s against me, ganging up on me, look,” said the former Mexico City mayor, 64.

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Independent candidate Jaime Rodriguez shot back: “It’s not ganging up, Andres, it’s that you say any old nonsense.”

Twice a runner-up for the presidency, Lopez Obrador has led polls for months, and one in the past week by newspaper Reforma put him 22 points ahead of Anaya.

At times he appeared amused by the verbal jousting, at others, distracted. At one point he deflected a round of criticism by simply pulling out a poster board with the Reforma numbers on it showing him with 48 percent support.

“It’s not to show off. 48 percent. Something terrible would need to happen..,” he added without completing the sentence, and then said his numbers would rise further. “That’s my reply.”

Anaya, 39, who heads a right-left alliance, and Jose Antonio Meade, candidate of the centrist PRI, have spent months battling each other for second place. But they took turns time and again to attack Lopez Obrador during the two-hour debate.

Meade, 49, called Lopez Obrador a “puppet of criminals” and described his political party as a “family business”.

Lopez Obrador defended his security plans, saying anemic growth had brought about a breakdown in law and order and noting “you can’t fight fire with fire”. He repeated his pledge to sweep corruption out of the government from “top to bottom.”

Lopez Obrador has cut a more relaxed figure on the campaign trail than in previous years, generally avoiding the kind of outbursts that in the past helped adversaries depict him as a radical menace to stability in Latin America’s No. 2 economy.

But he showed no great enthusiasm for the debate on Sunday and began leaving the stage while the camera was still trained on the five candidates at the close.

Anaya has struggled to shrug off accusations by the PRI that he laundered money in a 2014-2016 property deal, but he remained collected throughout the debate. He quickly rejected the allegations again to turn his fire back on the front-runner.

“Our coalition is the only one that can beat Lopez Obrador,” Anaya said during his closing remarks.