Sen. Markwayne Mullin, a Republican from Oklahoma, urged spring breakers with travel plans to Mexico to cancel their trips on Tuesday, citing violent conflicts in the country sparked by the Mexican military’s killing of cartel leader Nemesio Rubén Oseguera Cervantes—known as “El Mencho”—earlier this week.

Mullin shared these remarks during an appearance on CNBC’s “Squawk Box,” where he mentioned his chiropractor was still planning to visit a popular tourist destination in Mexico.

“Anyone who’s planning to go to Mexico for spring break … I mean, my chiropractor called me yesterday and said he’s still heading to Cancún, and I asked, ‘Are you crazy?’” Mullin stated.

“Nobody should travel there right now—it’s extremely volatile, and the United States is closely monitoring what’s unfolding,” he continued.

The senator’s comments come after [blank] conducted operations on Sunday in Tapalpa, Jalisco, targeting El Mencho, a former police officer who became leader of the Cartel de Jalisco Nueva Generación (CJNG), which U.S. authorities have identified as a major fentanyl supplier to the U.S.

El Mencho had a $15 million U.S. bounty on his head and rose to power following the arrest of Joaquín “El Chapo” Guzmán, the ex-head of the Sinaloa Cartel. Over the past 15 years or so, CJNG has grown from a regional criminal group into a global trafficking organization with its stronghold in Jalisco.

Mexico’s Defense Department said the operation was carried out as part of bilateral coordination and cooperation with the U.S., and that U.S. authorities provided supporting intelligence that contributed to El Mencho’s death.

After El Mencho’s death, [blank] and blocked roads in several Mexican states. Violent confrontations were also reported in parts of western Mexico.

Mexican authorities later announced the security situation had been “stabilized.”

“The security situation has now stabilized following targeted operations in Jalisco,” the Mexican Embassy in the U.S. said on Tuesday.

“Federal and state authorities are working to reopen transit corridors and restore public services smoothly,” the embassy continued. “Airline operations are normal, and international carriers are resuming flights today. Puerto Vallarta International Airport has reopened to domestic traffic.”

The embassy added: “If traveling through Jalisco, some local security measures remain in place while authorities restore airport operations to full capacity. We are collaborating with international partners to ensure safety and stability at all transit hubs and tourist destinations.”

However, the U.S. State Department’s travel advisory for Mexico remains in effect. The U.S. government earlier issued a shelter-in-place order for Americans in Mexico, but that order has since been lifted.

CJNG is considered Mexico’s most powerful cartel, with an estimated 19,000 members and operations across 21 of the country’s 32 states.

The Trump administration designated the cartel as a [blank].

Mullin said on Tuesday that the splitting of cartels after Mexico’s operation is a “great opportunity for us and Mexico to take them all out.”

“Now, will we eliminate all drug trafficking in the world? Absolutely not. But can we regain control of it? Absolutely,” he added.