In Mexico, 20 people were killed Sunday when gunmen opened fire on a crowd watching a cockfight in a small town in the western state of Michoacán. Police said they found more than 100 30-caliber shell casings at the crime scene. Mexico’s military has joined the search for the killers, but so far no arrests have been made.

Last year Mexico filed a lawsuit in a U.S. federal court seeking to hold 10 U.S.-based gunmakers accountable for Mexico’s epidemic of gun violence. The complaint says more than half a million U.S.-made guns are smuggled to Mexico each year.