MEXICO CITY (AP) — The Mexican army killed the leader of the Jalisco New Generation Cartel, Nemesio Ruben Oseguera Cervantes, “El Mencho,” on Sunday, decapitating what had become Mexico’s most powerful drug cartel and thrusting swaths of the nation into chaos.

The drug lord was the Mexican government’s biggest prize yet to show the Trump administration in its efforts to crack down on the cartels, and his death was met with a forceful reaction from the cartel, known by its Spanish initials CJNG.

Cars burned out by cartel members blocked roads in nearly a dozen Mexican states and left smoke billowing into the air. Jalisco’s capital, Guadalajara, was turned into a ghost town Sunday night as civilians hunkered down. School was canceled Monday in several states.

Oseguera Cervantes was wounded in an operation to capture him Sunday in Tapalpa, Jalisco about a two-hour drive southwest of Guadalajara and he died while being flown to Mexico City, the Defense Department said in a statement. The state is the base of the cartel known for trafficking huge quantities of fentanyl and other drugs to the United States.

During the operation, troops came under fire and killed four people at the location. Three more people, including Oseguera Cervantes, were wounded and later died, the statement said. Two others were arrested and armored vehicles, rocket launchers and other arms were seized. Three members of the armed forces were wounded and receiving medical treatment.

A Jalisco state official who requested anonymity because they were not authorized to speak publicly said that a member of the National Guard died in Tapalpa during the operation, six other National Guard members died in Zapopan beside Guadalajara, a jail guard was killed at a lockup in Puerto Vallarta when prisoners rioted, and an agent from the Jalisco state prosecutor’s office was killed in Guadalajara. Details were not immediately available.

The U.S. Embassy in Mexico said on X that the operation against Oseguera Cervantes was carried out by Mexican special forces “within the framework of bilateral cooperation, with U.S. authorities providing complementary intelligence.”

“Ever since President (Claudia) Sheinbaum has been in power, the army has been way more confrontational, combative against criminal groups in Mexico,” said David Mora, analyst for International Crisis Group in Mexico. “This is signaling to the U.S. that if we keep cooperating, sharing intelligence, Mexico can do it, we don’t need U.S. troops on Mexican soil.”

The killing of the drug lord set off several hours of roadblocks with burning vehicles, tactics commonly used by the cartels to block military operations. Videos circulating on social media showed smoke billowing over the tourist city of Puerto Vallarta in Jalisco, and people sprinting through the airport of the state’s capital in panic.

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. A number of Mexican and international airlines also canceled flights.