U.S. Secretary of State Hillary Rodham Clinton headed to Mexico City on Wednesday for talks that are expected to focus largely on growing U.S. concern about drug-related violence along Mexico's border that is increasingly spilling over into the United States. Clinton's two-day visit to Mexico City and Monterrey comes a day after President Barack Obama and Homeland Security Secretary Janet Napolitano unveiled plans to secure the U.S.-Mexico border by increasing manpower and technology in the U.S. Southwest. The administration has insisted that U.S.-Mexican relations will not be dominated by any one issue, and State Department officials said Clinton will discuss a variety of issues including trade, climate change and the global financial crisis in her meetings. Discussions are likely to touch upon last week's decision by Mexico to impose tariffs on 89 U.S. products after Congress cancelled a trial program that allowed Mexican truckers access to U.S. highways. But U.S. officials acknowledge that the drug violence is likely to be top of the agenda. While the violence is still predominately inside Mexico, reports of a leap in home invasions and kidnappings related to drug cartel activity has sparked major concern in Congress, prompting hearings and the Tuesday announcement of a new plan to tackle border security by the administration.