New Delhi, Feb. 23 -- Mexico was gripped by a wave of coordinated violence after the reported killing of Nemesio Ruben Oseguera Cervantes, widely known as "El Mencho", the alleged leader of the Jalisco New Generation Cartel (CJNG). As dramatic images of burning buses and highway blockades circulated from Puerto Vallarta and Guadalajara, the United States issued an urgent travel warning advising its citizens to shelter in place across several Mexican states.

Authorities in the state of Jalisco have declared a statewide "Code Red" after a high-profile law enforcement operation in the town of Tapalpa during the early hours of Sunday, in which Nemesio "El Mencho" Oseguera Cervantes was reported killed.

El Mencho was the head of the powerful...