Mexican authorities said the dramatic operation unfolded after a visit by a romantic partner of cartel boss Nemesio Oseguera, known as "El Mencho," helped security forces track him down. His capture and subsequent death led to a wave of retaliatory attacks.

Oseguera was considered Mexico’s most wanted drug lord and the head of the powerful Jalisco New Generation Cartel. Officials described him as the mastermind behind large scale drug trafficking and violent operations across the country.

Following the operation, 25 members of the National Guard military police were killed in revenge attacks by cartel fighters. The violence shocked the nation and raised serious concerns about security and stability.

The United States had earlier announced a reward of $15 million for information leading to his arrest, highlighting his global criminal profile and influence.

Security experts believe his death may weaken the cartel’s command structure, but they also warn that internal power struggles could lead to more bloodshed in the short term. Authorities have increased security in sensitive areas to prevent further violence.

The killing of such a big cartel leader can change the power balance. But revenge attacks show the cartel is still strong. Violence may continue for some time. The situation remains tense and uncertain.

He died in a helicopter after being injured in a military operation by Mexican special forces in a wooded area outside the town of Tapalpa in the western state of Jalisco, according to Mexico's defense ministry.

Defense Minister Ricardo Trevilla said information from a confidante of one of Oseguera's romantic partners helped officials quickly plan the raid for the following day at the crime boss' compound.

During the raid, Oseguera's gunmen opened fire on security forces and the conflict moved to a cabin complex in a wooded area, where he was injured along with two of his bodyguards. The three were transported by helicopter to Mexico City but did not survive.

"Unfortunately, they died on the way," Trevilla said, speaking at the president's daily press conference.

Oseguera's death triggered violence across Mexico, as cartel loyalists blocked roads and burned cars in retaliation against the government.

Security Minister Omar Garcia Harfuch told reporters at the press conference that 30 cartel members were killed in these attacks, as well as one bystander. At least 70 people were arrested in seven states.

According to the defense ministry, attacks in Jalisco were masterminded by Oseguera's right-hand man and top financial chief known as "El Tuli," who was also killed in a clash with security forces while they attempted to arrest him.

Garcia added that authorities were closely monitoring for a reaction or restructuring within the cartel that could unleash further violence. "There is already a specific surveillance of several leaders of this criminal organization," he said.

Officials said that U.S. intelligence was used to help pinpoint the exact location of the Tapalpa compound but underscored that Mexico led the operation.

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"There was no participation in this operation of U.S. forces. What there was, was an exchange of information," President Claudia Sheinbaum said.

Trevilla was moved to tears as he offered condolences to the relatives of Mexican security officers who died in the aftermath on Sunday, in which officials registered at least 85 roadblocks across Mexico. The flare-ups caused airlines to cancel flights on Sunday, and on Monday morning shares in Mexican airline Volaris and airport operators GAP and ASUR were down more than 4%.

Sheinbaum said the situation was normalizing and that her government's priority was ensuring peace and security.

U.S. President Donald Trump on Monday called on Mexico to boost its efforts targeting drug cartels. "Mexico must step up their effort on Cartels and Drugs!" he wrote in a social media post.

Oseguera's death deals a strong blow to the CJNG cartel, believed to be a major supplier of fentanyl to the U.S.

While the U.S. has pushed Mexico for more action on drug trafficking, Mexican authorities have also long called on the U.S. to do more to limit the illegal sales of firearms that bolster the vast arsenals of cartels that operate inside its territory. According to U.S. government data, some 70% of illegal arms traced in Mexico came from the U.S.