At least 30 gunmen burst into a drug-rehabilitation center in a Mexican border-state capital and opened fire, killing 19 men and wounding four people, police said Friday. Gunmen also killed 20 people in another drug-plagued northern city.

CIUDAD JUÁREZ, Mexico — At least 30 gunmen burst into a drug-rehabilitation center in a Mexican border-state capital and opened fire, killing 19 men and wounding four people, police said Friday. Gunmen also killed 20 people in another drug-plagued northern city.

The killings marked one of the bloodiest weeks in Mexico.

The bullet-riddled bodies of 18 men and two women were found Friday in five parts of Ciudad Madero, in the northeastern state of Tamaulipas, where violence has surged amid a turf battle between the Gulf cartel and its former ally, the Zetas gang.

More killings occurred late Thursday at the Faith and Life center in Chihuahua city, about 210 miles south of Ciudad Juárez, state police spokesman Fidel Banuelos said.

    Most Read Stories

Police have said some drug cartels are exploiting rehab centers to recruit hit men and smugglers, often threatening to kill those who don’t cooperate.