Suspected drug hitmen have killed 10 patients in a Mexican rehabilitation clinic, the second such attack this month in the city of Ciudad Juarez on the U.S. border, authorities said on Wednesday.
Drug gangs have targeted rehab clinics in the manufacturing city across from El Paso, Texas, accusing them of protecting dealers from rival gangs.
State attorney spokesman Vladimir Tuexi said the victims, nine men and one woman, were killed late on Tuesday as they finished praying before going to bed.
A similar attack took place in Ciudad Juarez, in the northern state of Chihuahua, earlier in September, when hooded gunmen killed 17 patients at another clinic, one of the deadliest assaults during President Felipe Calderon's three-year war against drug cartels.
Ciudad Juarez is the battleground for the feuding Juarez cartel and drug smugglers loyal to Joaquin "Shorty" Guzman, the head of the Sinaloa cartel and Mexico's most-wanted man.
The city's streets are constantly patrolled by 10,000 troops and federal police.
The government's inability to defeat the cartels is Calderon's biggest challenge and is worrying foreign investors and the United States. More than 13,000 people have been killed in drug-related violence since late 2006.
Calderon last week removed Attorney General Eduardo Medina Mora, who had spearheaded his anti-drug campaign, and nominated a little-known former law enforcement official as his replacement.
But his new pick, Arturo Chavez, could struggle to win congressional approval due to his record as top prosecutor in Chihuahua, where he failed to stop the murders of hundreds of young women in the 1990s.