U.S. President Barack Obama met with Canadian Prime Minister Stephen Harper and Mexican President Felipe Calderon at the White House Monday for a North American summit that focused on the economy and regional security.

In a press conference with his Mexican and Canadian counterparts, Mr. Obama said the United States has accelerated its cooperation with Mexico to fight the violent drug war that has left more than 50,000 people in that country dead since 2006.

“Criminal gangs and narco traffickers pose a threat to each of our nations. And each of our nations has a responsibility to meet that threat.”

On the economy, the three leaders said they discussed plans to simplify and eliminate regulations that are stifling trade between their countries.

The White House says Monday’s North American Leaders’ Summit is a chance for the three countries to expand cooperation on the economy and security. The meeting comes ahead of the broader Summit of the Americas, which begins April 14 in Colombia.

They last held a summit in 2009 in Mexico, and this year’s gathering will be the last for this group of leaders, as Mr. Calderon’s term in office ends in December. Mr. Obama is up for re-election in November.

U.S. Defense Secretary Leon Panetta met last month with his Canadian and Mexican counterparts to discuss ways to fight drug trafficking – a key problem plaguing Mexico. President Calderon launched a massive military crackdown against drug cartels after taking office in 2006.