The U.S. government found no direct connection between the president and criminal groups, the Times reported. It never opened a formal probe. “There is no investigation into President López Obrador,” the Justice Department said in a statement.

López Obrador responded Thursday that the charges were false and unsupported by any documentation.

The report came at a delicate moment. López Obrador has been a crucial partner to the Biden administration as it tries to slow irregular migration. U.S. officials are also urging Mexico to crack down on the production of deadly fentanyl.

But earlier this month, the Mexican leader nearly canceled a high-level meeting on fentanyl and migration after other news reports raised questions about alleged drug money in his first presidential campaign in 2006. López Obrador denied those allegations. The Feb. 6 meeting went ahead after President Biden called his Mexican counterpart.

The controversy hasn’t, however, died down. The reports about the unsuccessful 2006 campaign spawned a hashtag #narcopresidente — narco president — which exploded on social media. López Obrador’s opponents have seized on the drug allegations as they try to dislodge his party from office in national elections on June 2. The president’s protégé, former Mexico City Mayor Claudia Sheinbaum Pardo, has a wide lead in polls.

López Obrador said Thursday that he intended to maintain good relations with Washington — but U.S. agencies would not be allowed to investigate Mexican officials.

“There is cooperation, there has to be,” López Obrador told his daily news conference. “But we won’t accept subordination, or interventionism.”

How a crucial U.S.-Mexico anti-drug alliance fell apart as fentanyl took off

The Mexican leader has had frosty relations with the U.S. Drug Enforcement Administration since he took office in 2018. López Obrador declared the U.S.-backed drug war a failure and announced a policy known as “hugs, not bullets” — relying on social programs to keep people from joining drug gangs.

Cooperation with the DEA nearly collapsed after the agency secretly investigated a former Mexican defense minister, Salvador Cienfuegos, on drug charges, leading to his 2020 arrest in Los Angeles. The Trump administration freed him amid an outcry by Mexico’s government. Yet the DEA’s ability to operate was severely curbed, just as Mexico was emerging as the No. 1 source of fentanyl to the United States.

The Times cited two accounts of alleged contacts between López Obrador’s aides and drug traffickers. In one, an informant described a meeting with Ismael “El Mayo” Zambada García, a leader of the Sinaloa cartel, before López Obrador won the 2018 election. In the second, another informant said that a founder of the Zetas cartel gave $4 million to two of his allies in an effort to win release from prison.

The report did not identify the president’s aides allegedly involved in either case. It’s not clear whether the reports were ever independently confirmed, the Times reported.

In a third case, the Times reported, a source told U.S. agents that trafficking groups had videos of the president’s sons receiving drug money.

The American ambassador to Mexico from 2019-2021, Christopher Landau, told The Washington Post that he was never informed of any such allegations. “It raises questions about how seriously this was taken, or what level of confidence” the DEA had in the information, he said.

As fentanyl crisis grows, U.S.-Mexico divide deepens

A former senior DEA official, speaking on the condition of anonymity to protect his current private sector job, said he was aware of informants’ accounts of drug money flowing into López Obrador’s campaigns. But to build a case, agents would need authorization from a high-level committee that would weigh possible implications for U.S. foreign policy. That permission wasn’t sought, he said.

“We already knew what the answer was going to be,” he said.

For decades, drug-trafficking groups have penetrated the Mexican government. A year ago, one of the U.S. government’s closest partners in the drug fight, Genaro García Luna, who was public-security minister from 2006-2012, was found guilty in U.S. federal court of accepting bribes from the Sinaloa cartel.

Critics have often questioned whether López Obrador adopted his “hugs not bullets” approach because he’d cut a deal with drug groups. Yet Falko Ernst, a senior Mexico analyst for the International Crisis Group, said that the president’s policies actually weren’t that different from those of his predecessor. López Obrador, for example, captured Ovidio Guzmán, a son of famed druglord Joaquín “El Chapo” Guzmán, and extradited him to the United States to face drug-trafficking charges.

“This administration has been pushing a narrative that is sometimes quite starkly disconnected with realities on the ground,” he said.

López Obrador frequently tries to discredit journalists who write critically about him, and Thursday’s news conference was no different. In ridiculing Times correspondent Natalie Kitroeff’s efforts to get comment on the drug story, the president revealed her phone number.

Jan-Albert Hootsen, Mexico representative of the Committee to Protect Journalists, said the move was unethical in a country with high rates of violence against reporters. “The Mexican press and foreign press here already have more than enough security concerns,” he said.

Devlin Barrett in Washington and Lorena Rios in Monterrey, Mexico, contributed to this report.