Mexican security forces have killed a drug lord who led one of the most powerful criminal organisations in the country, triggering a wave of violence in several areas, including the western state of Jalisco.

The Mexican Secretariat of National Defence said Nemesio Ruben Oseguera Cervantes, also known as “El Mencho”, was wounded in a clash with soldiers in the town of Tapalpa, in Jalisco state, on Sunday and died while being flown to Mexico City.

He had a $15m bounty on his head from the United States.

The Mexican operation set off a wave of ⁠violence, with gunmen torching cars and blocking highways in more than half a dozen states, including Jalisco, Colima, Michoacan, Nayarit, Guanajuato, and Tamaulipas.

Jalisco’s capital, Guadalajara, which will host several matches in the upcoming FIFA World Cup, was turned into a ghost town on Sunday night as civilians hunkered down.

Videos circulating on social media showed people sprinting through the Guadalajara airport in panic and smoke billowing over the tourist city of Puerto Vallarta.

Jalisco Governor Pablo Lemus told residents to stay home and suspended public transportation.

School was cancelled on Monday in several states.

Mexican President Claudia Sheinbaum praised the country’s security forces in a post on X and called for calm.

“There is absolute coordination with the governments of all states,” she wrote. “In the vast majority of the national territory, activities are proceeding with complete normality.”

‘Great development for Mexico’

Oseguera, 59, is one of the biggest Mexican drug lords to be taken down since the capture of the founders of the Sinaloa cartel, Joaquin “El Chapo” Guzman and Ismael Zambada, who are now both in US custody.

The Mexican Defence Secretariat said Sunday’s raid was carried out with “complementary information” from US authorities. It said four members of Oseguera’s Jalisco New Generation Cartel (CJNG) were killed in the raid, while two others died during their transfer to Mexico City.

Two more were arrested, and armoured vehicles, rocket launchers and other arms were seized, it said. Three members of the armed forces were wounded and are receiving medical treatment, it added.

US Deputy Secretary of State Christopher Landau welcomed the operation and called Oseguera “one of the bloodiest and most ruthless drug kingpins”.

“This is a great development for Mexico, the US, Latin America, and the world,” he added.

The US State Department warned Americans in the states of Jalisco, Tamaulipas, Michoacan, Guerrero and Nuevo Leon to remain in safe places due to the ongoing security operations.

Canada also issued a travel warning for some areas, citing “shootouts with security forces and explosions” in Jalisco, Guerrero and Michoacan. It warned its citizens in Puerto Vallarta to shelter in place and keep a low profile in Jalisco.

Air Canada announced it was suspending flights to Puerto Vallarta “due to an ongoing security situation” and advised customers not to go to their airport.

United Airlines ‌and American Airlines also said they have cancelled flights to Puerto Vallarta and Guadalajara.

El Mencho and CJNG

The military operation against Oseguera follows a pressure campaign from the administration of US President Donald Trump on Sheinbaum’s government to ramp up its crackdown on drug trafficking, including threats to intervene directly in Mexico.

Oseguera, a former police officer and avocado farmer, co-founded the CJNG around 2007, and built it into what the FBI considers Mexico’s most powerful trafficking organisation, responsible for the bulk of cocaine, heroin, methamphetamine and fentanyl entering the US.

He cultivated an air of mystery throughout the country, keeping such a low profile that all known photographs of him were decades old.

Al Jazeera’s John Hollman, reporting from Mexico City, said Oseguera was “the undisputed head” of the CJNG and “the most powerful Mexican drug trafficking figure that was free in the country”.

He called the kingpin’s killing a “triumph” for Sheinbaum’s government, but said it could unleash a wave of violence across Mexico.

“There is no obvious successor to Oseguera. His brother is in a US prison, and his son, called El Menchito, is also in prison. As is his daughter. We could now see different regional bosses in the cartel start disputing for power. We saw this happen before. When El Chapo was arrested, it eventually sparked a civil war between the different Sinaloa factions,” Hollman said.

The timing is particularly sensitive, our correspondent noted, with Mexico set to host the FIFA World Cup and Guadalajara serving as a host city.

“So, what looks like a government triumph today could become a significantly bigger security crisis in the months ahead,” he said.

Analysts said Mexico’s military needed to move quickly to limit any violence.

“Killing or capturing the head of the cartel is not really going to have a major impact. They have to go after the infrastructure, their logistics, the money laundering, their armed wings,” said Mike Vigil, the former chief of international operations at the US Drug Enforcement Administration.

“What they have to do is launch a frontal assault based on intelligence, and basically diminish the infrastructure of this cartel. And they have to do it quick and they have to do it efficiently, because if not, there is going to be hell to pay in terms of violence,” he said.

Vigil said the Trump administration has done little to address the US side of the equation, despite pressuring Mexico on drug trafficking.

Hundreds of thousands of weapons flow from the US into Mexico annually – a stark contrast to Mexico’s single military-run gun store, which sells just 6,500 firearms a year – yet the Republican Party has shown no appetite for curbing those exports, he said.

Similarly, the administration has made no meaningful push to reduce domestic drug demand, he said.

“If there is no demand or consumption, there’s not gonna be any cartels. It is a big problem,” he said. “But the Trump administration does nothing in terms of drug education, treatment of drug addiction – none of that.”