Mexican drug kingpins have moved their focus towards synthetic drugs such as methamphetamine and fentanyl, which are easier to mass-produce and smuggle, officials have said.

The shift in their operations is evidenced by the nature of recent drug seizures by Mexican law enforcement, which were detailed by the country’s defense secretary. The Department of Defense, which is working closely with the civilian authorities to crack down on cartels, updated the public on its efforts on Monday.

“There was a change in consumption [and] a change in drug markets due to the ease of producing synthetic drugs,” said General Luis Cresencio Sandoval, speaking at a news briefing alongside the nation’s president.

Marijuana, cocaine, and heroin, which all require the cultivation and production of herbal raw materials, have fallen out of favor, while synthetic drugs have become more prominent, the official said. Narcotics such as methamphetamine and fentanyl are easier to produce and transport, and offer drug lords greater profit margins, the general stated, explaining the trend.

Recent drugs seizures have reflected this change. According to Sandoval, the volumes of confiscated fentanyl grew by a staggering 525% in the three years since President Andres Manuel Lopez Obrador took office, compared to the three previous years. The same metrics for methamphetamine, cocaine, and heroin were 128%, 77%, and 26%, respectively.

Mexico law enforcement has seized a record 1,852kg (4,083lb) of fentanyl this year, compared to just 15kg (33lb) in 2016. Total drug confiscations since December 2018, the start of the current administration, have so far totaled 3,497kg (7,710lb) for fentanyl, 124,735kg (274,994lb) for methamphetamine, 62,020kg (136,730lb) for cocaine, and 1,398kg (3,082lb) for heroin, Gen. Sandoval reported.

Explaining why his department had raided fewer labs in the past three years than in the previous period, the general said the cartels had been using increasingly large-scale facilities to produce or repackage narcotics. He also reported a decrease in homicides linked to organized crime, a decrease in casualties sustained by the military during anti-cartel operations, a decrease in human rights complaints against the military, and other signs of progress.