And Leonhart said that in addition to ramped up pressure on the cartels, the streets have felt the pinch: "The price of cocaine, in 24 months, has increased 104 percent, while the purity has decreased 34.8 percent."
In addition, agents have seized $59.1 million in cash, and an additional $6.5 million in assets, including 149 cars, three aircraft, three maritime vessels and 169 weapons.
The U.S. State Department has also warned of the situation throughout Mexico, cautioning U.S. citizens living in and traveling to that country to be vigilant.
"Mexican drug cartels are engaged in an increasingly violent conflict -- both among themselves and with Mexican security services -- for control of narcotics trafficking routes along the U.S.-Mexico border," the current alert says.
Kidnappings, daytime shootouts in public places and a "fluid" situation in northern Mexico have all contributed to the heightened security situation there, the warning states.
And in a startling example of the direness of the situation, the mayor of Juarez, Mexico is reportedly seeking refuge in this country as his family's only escape from threats of violence.
"We received information that the Juarez mayor lives in El Paso, and that possibly they were going to come to El Paso to get him," El Paso Police detective Carlos Carrillo said Monday. "He has not asked us for our help, but it's our duty to protect any resident of our city who may be under threat."
The State Department notes in its alert that "The situation in Ciudad Juarez is of special concern," adding that Mexican authorities have reported more than 1800 killings in the city of 1.6 million since January 2008. Car theft and carjackings in the area have also reached troubling levels, the warning added.
ABC News' Jason Ryan and Jack Date contributed to this report.