WASHINGTON (AP) — Days before taking office, President-elect Barack Obama is meeting Mexican President Felipe Calderon, a pre-inauguration tradition that comes as Mexico’s drug violence escalates and spills into the United States.

Obama transition officials say that today’s session, to be held at the Mexican Cultural Institute in Washington, is intended to underscore the importance of the relationship between Mexico and the U.S.

Mexico’s drug war has increasingly defined that relationship. U.S-Mexico ties remain strong, but immigration and trade concerns loom along with security matters.

Drug-related homicides doubled in Mexico last year, led by rising murder rates in cities across the border from the U.S. The Justice Department last month called Mexican cartels the biggest organized crime threat to the United States.

Calderon, whom U.S. officials have praised for deploying troops to fight cartels and capturing top drug kingpins, already won a multimillion-dollar anti-drug aid package from Washington last year. Obama supports that plan, known as the Merida Initiative, and promises to take up another cause that Calderon champions: a stop to smuggling guns from the U.S. to Mexico.