Obama on Thursday said there was an important role for his country in helping to combat the drug war and organized crime in Mexico.
The president said that the US had a duty to help Mexican authorities end the violence that has claimed more than 60,000 lives in the past six years, by stemming demand for drugs north of the border.
Obama held talks with his opposite number, President Enrique Pena Nieto, at Mexico City's National Palace at a time when the Mexican government is embarking on a rebalancing of its security strategy.
At a press conference, Obama said he had: "reaffirmed our determination in the United States to meet our responsibilities to reduce the demand for illegal drugs and to combat the southbound flow of illegal guns and cash."
"I agreed to continue our close cooperation on security even as the nature of that evolves," said Obama. "It's up to the Mexican people to determine their security structures and how they engage with other nations including the United States."
A different approach
During his six-year presidency, which ended in December last year, Pena Nieto's predecessor Felipe Calderon allowed US agencies to deal directly with Mexican counterparts.
Nieto has instead said he wants all action against organized crime to be directed by the country's interior ministry.
The Mexican president insisted the new strategy was aimed at producing "better results."
At the conference, Obama and Pena Nieto announced the creation of an economic forum to deepen trade links, saying these should be the true focus of relations.
"Mexico and the United States have one of the largest, most dynamic relationships of any two countries on Earth," Obama said. "And yet, we all don't always hear about all aspects of these extraordinary ties because too often, two issues get attention: security or immigration."
Optimism over immigration bill
However, with 11 million migrants without documentation living in the US - two thirds of them from Mexico - the subject of immigration was inevitably on the agenda.
Obama said he was "optimistic" that a bipartisan bill to create a process of naturalization would be approved by the US Senate. Pena Nieto sidestepped a question from journalists on the matter, claiming it was an "internal issue" for Obama while wishing him "success."
Obama was on Friday set to head on to Costa Rica for summit talks with Central American leaders.
rc/jm (AFP, AP, dpa, Reuters)