A state congressional candidate and his whole family members were killed at home on Saturday in Mexico's southern Gulf coastal state of Tabasco, the latest in a spate of violence that has plagued the Latin American nation for more than two years.

Jose Francisco Fuentes Esperon, 43, was found dead by relatives along with his wife and two sons in the state capital of Villahermosa, local press reported.

After the incident, the state government offered immediate protection for all candidates who will run in the Oct. 18 elections, state Attorney General Rafael Gonzalez Lastra said.

President Felipe Calderon also urged a thorough investigation into the brutal murder case.

Also on Saturday, 11 other people were killed in separate incidents in Mexico. In the southern state of Guerrero, police found the bodies of two boys who had gone missing a week earlier. In Santiago in the northern Mexican state of Nuevo Leon, five gunmen and a bystander died in a shootout between assailants and the army.

According to the army, the assailants belong to a group of drug enforcers tied to the Gulf cartel which carried out kidnappings, extortions and drug sales.

More than 4,000 people have been killed this year in incidents linked to organized crime.

Residents have been fleeing their homes in the northern city of Ciudad Juarez after the deaths of 18 people on Wednesday.

"We are looking for another home," said a former resident of Ciudad Juarez. The city of 1.3 million people saw the worst of the nation's drug violence that has claimed more than 1,600 lives so far this year.

Gunmen attacked a rehabilitation center in the city on Wednesday night, killing 18 and injuring another five.

Some 75 people have been killed in several incidents in Juarez, a favored spot for smuggling cocaine into the United States.

The authorities said vying for profits among drug gangs is a possible motive for rampant killings.

According to Adrian Franco Zevada of the Attorney General's Office, drug dealers' profits come primarily from 20 percent of the drug users who are defined as hard core addicts.

Innocent civilians and politicians have continued to fall victim to violence despite a war waged by the Mexican government to curb violence.

More than 45,000 Mexican army troops have been deployed to aid the fight against organized crimes and drug cartels, the top priorities of Calderon's administration since he took office in late 2006.

The strategies the government adopted on the two fronts include establishing legal tools and draining the financial resources of the drug gangs.

Many experts believe that a necessary step for the government to crack down on drug-related violence is to purge corruption in the police and judiciary.

Experts have noted that increased and sustained cooperation with the United States is necessary for stemming drug-related violence. About 90 percent of the cocaine that enters the United States is trafficked through Mexico.

Meanwhile, a statement released by the U.S. embassy on Wednesday said that a long-term cooperation between the United States and Mexico is also good for the two countries in their joint battle against drug trafficking.

The statement added that the United States had already sent to Mexico X-ray scanners, armored cars and a mobile test laboratory and would provide it with helicopters and help train 1,500 drug detectives.

(Xinhua News Agency September 6, 2009)