Police and forensic experts recover bodies from the desert
Gun battles between suspected drug gang members and troops have left 21 people dead in northern Mexico, police say.
The violence began when gunmen dragged nine people, including police, out of their homes in a farming town in Chihuahua state and shot six of them.
Troops pursued the attackers through the desert, exchanging fire that left 15 people, including one soldier, dead.
In another incident, armed men broke into a prison in the state of Coahuila, killing three inmates before escaping.
State prosecutors said the eight heavily armed men forced their way into the jail in the city of Torreon on Monday, singled the three prisoners out, beat them to death and then set their bodies on fire.
Before fleeing, the assailants freed nine other inmates.
The men who were killed had been transferred to the prison just a couple of hours before the attack and were being held on kidnapping and murder charges.
Mexico has seen drug-related violence soar since President Felipe Calderon began deploying some 40,000 troops in December 2006 to tackle the drug gangs.
Last year saw more than 5,600 drug-related murders as traffickers fought federal forces and among themselves.
One of the worst-affected areas has been Chihuahua state, where Tuesday's shootout happened.
Suspected drug gang members arrived in Villa Ahumada, a farming town some 130km (80 miles) south of the violence-hit city of Juarez on the US-Mexico border and seized nine people.
Six of the hostages were then shot dead. On hearing the shots, soldiers quickly arrived on the scene and gave chase.
In the gun battles that followed, 14 of the suspected attackers and one soldier was killed.
"The bodies were strewn across the desert," said army spokesman Eduardo Torres.
People in Villa Ahumada said they saw a convoy of vehicles drive through the town before dawn on Tuesday, while some later heard shots.
"People are really afraid of a revenge attack by hitmen after this violence," a local man told Reuters.
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