Mexico Security Minister Omar Garcia Harfuch said that 25 members of the National Guard and one security guard died in cartel attacks following the capture and death of infamous cartel boss Nemesio Oseguera, alias “El Mencho,” on Sunday.

Oseguera, Mexico’s most-wanted cartel leader, was the mastermind of the powerful Jalisco New Generation Cartel (CJNG).

He died in custody after being injured in a military operation by Mexican special forces in the town of Tapalpa in Jalisco state, according to Mexico’s defence ministry.

Mexico Defence Minister Ricardo Trevilla said on Monday that information leading to Oseguera’s capture and death stemmed from a romantic partner of the crime boss. The U.S. had offered a $15 million reward for information leading to his arrest.

His death triggered waves of violence across Mexico, as cartel operatives blocked roads, burned cars and pursued retaliatory attacks.

El Mencho’s death triggered “27 cowardly attacks against authorities in Jalisco,” Harfuch said at the president’s daily press conference on Monday, adding that 30 cartel operatives were killed as well as one bystander. At least 70 people were arrested in seven states.

“We are closely monitoring for any kind of reaction or restructuring within the cartel that could lead to violence,” he said.

U.S. PresidentDonald 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.