Machine guns, grenades and other weapons used by drug gangs in Mexico to kill rivals and wage territorial battles across the country come from the United States, President Vicente Fox's spokesman said.
"The volume of high-technology weapons that enter Mexico and are in the hands of drug traffickers and other professional criminals are those that come from the United States," Ruben Aguilar said at his daily briefing.
A wave of killings and mayhem in the Mexican border city of Nuevo Laredo prompted U.S. Ambassador Tony Garza to shut down on Monday all but emergency services at the American consulate. The shutdown was expected to last a week, and angered the Mexican government.
The decision to close the consulate was prompted in part by a high-powered shootout between attackers who used machine guns, grenades and a rocket launder against a private home in southern Nuevo Laredo -leaving a usually quiet residential street resembling a war zone.
More than 100 people have been killed in Nuevo Laredo this year, including nearly 20 police officers. Authorities on both sides of the border say Mexico's two main drug gangs are fighting for control of the area's smuggling routes into U.S. territory. The violence has continued largely unabated, even after Fox sent federal agents and soldiers to restore order.
Despite the continuing violence in the city across the border from Laredo, Texas, Mexico branded Garza's decision extreme and suggested such actions should only be taken during a war.
Garza met Wednesday with Interior Secretary Carlos Abascal, who emerged from the closed-door discussions saying both sides had reached a temporary agreement to reopen the Nuevo Laredo Consulate in the next few days.
Aguilar said Garza and Abascal did not discuss U.S. weapons brought into this country illegally during Wednesday's meetings, but that the topic was a serious concern of Fox's government.
He insisted the shuttering of the consulate had not strained Mexico-U.S. relations, calling them "very good."
Explosives and automatic weapons are not unique to violence in Nuevo Laredo. Early Monday, two assailants lobbed grenades into a crowded cockfighting ring in the western state of Jalisco, killing four and injuring more than two dozen.
Automatic weapons, meanwhile, are used in drug-related attacks and killings, kidnappings and armed robberies all over the country.
Also Thursday, Aguilar said a Fox plan to use federal authorities and soldiers to crackdown on drug-related violence along the border "has produced results _ not all the results we thought it would or wanted it to, but that's why Mexico's government has made the decision to increase the level of effectiveness of this operation."
Aguilar has said in recent days that Public Safety Secretary Ramon Martin Huerta will soon announce concrete plans to amplify and fortify the program, called "Mexico Seguro," or "Safe Mexico,", the AP reports.