It was also reported that two of Lopez Obrador’s aides accepted $US4 million ($6.1 million) in return for releasing a leader of the rival Zetas cartel after he won office.

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The Mexican president, who is in the final months of his term and is constitutionally barred from running for reelection, denied all the allegations made by the informants.

But Xochitl Galvez, the candidate for the centre-right opposition party Broad Front, called for an official investigation into Lopez Obrador over the claims in order “to know … the scale of corruption in his government.”

“No one is above the law,” she said.

The allegations are not the first time that the 70-year-old left-wing populist has been linked to drug traffickers, who have long attempted to infiltrate the Mexican state.

A separate investigation by the DEA launched more than a decade ago, and first reported on by media outlets last month, unearthed allegations that a powerful cartel leader known as “Barbie” donated some $US2 million ($3 million) in cash to Lopez Obrador’s first, unsuccessful presidential campaign in 2006.

The investigation was eventually closed without charges being brought.

Lopez Obrador’s attack on the Times echoed previous verbal assaults he has launched on journalists, including revealing private information about them.

The newspaper criticised his move on social media.

“This is a troubling and unacceptable tactic from a world leader at a time when threats against journalists are on the rise,” the media outlet said.

Experts warned his reaction to the New York Times’ reporting would heighten the dangers faced by media workers in a country where more than 160 have been murdered since 2000, according to local free speech group Article 19.

“Lopez Obrador needlessly and willingly exposed a reporter to an increased risk of threats and harassment in what continues to be the most dangerous country for journalists in the Western Hemisphere,” Jan-Albert Hootsen, the Mexico coordinator of the Committee to Protect Journalists, said.

“It is deeply concerning to us that he believes himself to be above the law and is completely unrepentant when challenged.”

Lopez Obrador’s stance towards the drug cartels has long concerned the United States.

His 2018 campaign slogan was “hugs not bullets” as he pledged to tamp down the narco violence by ordering security forces to avoid shoot-outs with the cartels.

Any DEA investigation of senior figures in Mexico’s government would require high-level approval in Washington, including, possibly, from Joe Biden.

The White House, however, has carefully attempted to avoid antagonising Mexico in recent years, whose cooperation it needs to tackle migration and the flow of cocaine and fentanyl into the United States.

The Telegraph, London