MEXICO CITY , Mexico ( CNN ) -- Gunmen shot and killed 17 patients and wounded two others in a drug rehabilitation center in northern Mexico late Wednesday , the mayor of Ciudad Juarez said Thursday . Police gather at the rehab facility where 17 people were killed in Ciudad Juarez , Mexico , late Wednesday . Mayor Jose Reyes Ferriz said authorities believe a rival drug gang attacked the men at the El Aviane rehab facility . `` At the very least , it was one organized crime group thinking that another group was operating in that place , '' Reyes told CNN . Wednesday night 's shootings , he said , are similar to an attack at a drug facility in March that left 20 patients dead . A Mexican civic group said last week that Ciudad Juarez , across the border from El Paso , Texas , had the most slayings per capita in 2008 of any city in the world . Watch scene at rehab center after shootings » . More than 1,420 people have been killed in Juarez this year , Reyes told CNN on Monday . About 1,600 people were killed in Juarez in 2008 , Reyes said . The latest Juarez killings came on the same day that gunmen shot dead the No . 2 security official and three others in Michoacan , the home state of Mexican President Felipe Calderon . Jose Manuel Revuelta Lopez , the deputy public safety secretary of Mexico 's Michoacan state , was killed in a shootout that also claimed the lives of two of his bodyguards and a bystander caught in the crossfire , said Jesus Humberto Adame Ortiz , spokesman for the state . Revuelta was leaving his office at 5:15 p.m. in the state capital , Morelia , when the shooting occurred , Adame said . An unprecedented wave of violence has washed over Mexico since Calderon declared war on drug cartels shortly after coming into office in December 2006 . More than 11,000 people have since died , about 1,000 of them police . The offensive against the government has been especially fierce in Michoacan . In July , La Familia Michoacana drug cartel was accused of assaults in a half-dozen cities across the state and of torturing and killing 12 off-duty federal agents and dumping their bodies on a remote road . That violence was thought to have been retaliation for the arrest of a La Familia leader . In Juarez , much of the violence is being committed by the rival Sinaloa and Juarez drug cartels , which are fighting for lucrative routes into the United States as well as local street sales , Reyes said . The deportations of thousands of Mexicans who have served time in U.S. jails into Ciudad Juarez are adding a deadly ingredient to an already volatile state of security , he said . In the past 45 days , 10 percent of those killed in Juarez had been deported from the United States in the past two years , Reyes said . `` We do n't have the statistics to know if they were criminals from the United States or not , '' he told CNN . `` We know they were deported from the U.S . Most of them come from U.S. jails . They end up in the city of Juarez , and that 's a problem generated for us , but also for the United States . '' Most deportees are simply Mexicans who crossed the border illegally , but some hardened criminals get involved with the gangs , which have networks in the United States , Reyes said . According to a report released last week by the Mexican Citizens Council for Public Security watchdog group , Juarez had an estimated rate of 130 killings per 100,000 people . The city has a population of around 1.5 million . By comparison , the homicide rate in New Orleans , Louisiana , the deadliest city in the United States in 2008 , was 64 homicides per 100,000 residents , based on preliminary FBI figures . CNN 's Arthur Brice and Mariano Castillo contributed to this report .
NEW : Ciudad Juarez mayor says authorities believe drug gang attacked rehab center . Slayings add to grim statistics for Juarez , ranked deadliest city in the world . The Associated Press contributed to this report. Mexico has seen wave of violence since president declared war on drug cartels .