U.S. Secretary of State Rubio acknowledged that political violence in Mexico is "real" and said he would work to stop arms trafficking following the murder of two government aides on Tuesday.

Rather than intervening unilaterally against the cartels in Mexico, the administration should return to the era of greater national security collaboration with its Mexican counterparts.

An attack on a political event in Mexico, where a mayoral candidate and three others were killed, is the latest in an uptick in political violence in the country.

A candidate for mayor and three of her supporters were murdered on Sunday during a campaign event in Texistepec, Veracruz, authorities said.

Mexico is dealing with another wave of violence. In the state of Guanajuato, seven people were killed during a Catholic festival, and two officials were murdered in the country's capital. Authorities suspect that drug cartels are behind the attacks.

Organized crime and violence in the Mexican state of Sinaloa has forced a local sanctuary to close and transfer at least 700 animals – including elephants, tigers, lions, ostriches, chickens, monkeys,

Tigers, monkeys, jaguars, elephants and lions are among the animals being moved due to the cartel violence​ eclipsing the northern Mexican city of Culiacan.