A convoy of gunmen chased their target into a home in the resort city of Acapulco and sprayed the residence with bullets on Tuesday, killing two small children and an elderly woman inside, authorities said.
Police in Guerrero state, where Acapulco is located, said witnesses reported the man tried to escape from the attackers by hiding inside the house. A woman, 60, was killed, along with two boys ages 2 and 6, police said in a statement. A 23-year-old woman was also wounded.
It was not clear what happened to the man being chased. Police found more than 200 shell casings at the scene in Acapulco, which has been the scene of bloody cartel turf battles.
The Interior Department condemned that and other attacks in Acapulco Tuesday that killed a total of eight people, saying "they illustrate the need to carry on with vigor the fight against organized crime." The statement said federal prosecutors would help their state counterparts investigate the killings.
In a separate attack in the Pacific coast resort, state police said a 15-year-old boy was killed along with two other men.
Hours earlier, another 15-year-old boy was shot in the head and killed outside his school, according to a police statement. A threatening note was left next to his body _ a common calling card of drug gangs.
Youths have increasingly been targeted in killings or died as bystanders caught up in Mexico's drug war, which has resulted in more than 35,000 casualties since December 2006, when President Felipe Calderon launched a stepped-up offensive against cartels.
Also Tuesday, the bullet-ridden bodies of two men were found in a taxi in elsewhere in Acapulco, and threatening notes were left next to a mutilated body found inside a plastic bag left near the state prison. Authorities did not disclose the notes' content.
And in the northern border state of Tamaulipas, a car bomb exploded outside the offices of municipal police in Ciudad Victoria, the local capital. The state government said in a statement that a police officer and an administrative employee suffered non life-threatening wounds.
The blast damaged a patrol vehicle and four private cars parked nearby.
Meanwhile, a judge ordered the son of a top cartel leader to stand trial on money laundering charges.
Prosecutors showed that Vicente Carrillo Leyva transferred illegally acquired funds within Mexico, the federal Attorney General's Office said in a statement.
Carrillo Leyva allegedly inherited a top position in the Juarez cartel from his father, Amado Carrillo Fuentes, who was considered Mexico's No. 1 drug trafficker when he died in 1997 during plastic surgery to change his appearance.
Carrillo Leyva was arrested in 2009 while exercising in a Mexico City park.
The Juarez cartel has been locked in a fight with the Sinaloa drug cartel for the border city of Ciudad Juarez that has killed more than 6,000 people in the last two years.
Also Tuesday, police in the resort city of Cancun found four bodies that had been set on fire, authorities said.
Quintana Roo state prosecutor Francisco Alor said the four men had been shot and their bodies burned in an open field in the outskirts of the city. All had their arms tied behind their backs.
Soldiers in the Gulf state of Veracruz found an apparent cartel training camp over the weekend. The Defense Department said in a statement that soldiers seized 17 automatic rifles, grenade launchers, grenades and hundreds of bullets.
The Mexican army also announced Tuesday that soldiers had seized five metric tons of marijuana in the border city of Miguel Aleman, across the border from Roma, Texas.
Soldiers on routine patrol found the marijuana in an abandoned structure on Monday after detecting a strong smell.