Mexican authorities are facing gunfire from increasingly well-armed traffickers and officials say the vast majority of the weapons are smuggled from the United States.
Assistant Secretary of Public Safety Patricio Patino made a fresh appeal Tuesday for U.S. authorities to cut off the supply.
"The firepower we are seeing here has to do with a lack of control on that side of the border," Patino said in an interview with The Associated Press. "What we have asked the American government ... is that they put clear controls on the shipments of weapons."
Illustrating that point, Patino said that early Tuesday, federal agents arrested two suspected drug gunmen carrying assault rifles and half a dozen hand grenades in the western city of Morelia, apparently as they were on their way to carry out a hit.
The attacks on authorities, which have resulted in the deaths of five soldiers and a top anti-drug official this month, come in response to a "radical change" in Mexico's law enforcement strategy, Patino said, noting that Mexico is now going after the cartels' entire structures rather than just leaders.
The administration of President Felipe Calderon has sent large detachments of soldiers and federal police into areas where traffickers operated almost openly, prompting intense attacks on security forces, including previously rare attacks on army patrols.
Patino said there is no indication that the cartels want to take on the army directly, the way leftist rebels involved in drug trafficking systematically confront the Colombian army. "I don't believe that organized crime has specifically targeted the army," he said.
Soldiers have not been the only ones caught in the drug battles. About 1,000 drug-related killings, many of them carried out by drug gangs against their rivals, have been recorded this year, a rate that would soar past last year's death toll of 2,000.
On Monday, gunmen launched a coordinated attack on a high-ranking intelligence official who investigated drug smuggling. He was shot dead in a sport utility vehicle on his way to work at the attorney general's office in the Mexican capital.
The army's role in the anti-drug war has led to other problems, however. On Tuesday, the director of the National Human Rights Commission said soldiers assigned to fight drug cartels have been accused of drugging, beating and raping four teenage girls over several days.
Jose Luis Soberanes said the government commission has testimony of the abuse from the girls and their families in mountainous Michoacan state, where 7,000 soldiers have been battling gangs and burning marijuana crops.
A medical examination confirmed that a 17-year-old girl had been raped, Soberanes said. The other three, ages 16 and 17, still were being examined.
The Defense Department said it will fully cooperate with an investigation and seek the maximum punishment for any soldier found guilty of abuse.