Mexico's ambassador to the United States says there must be extensive cooperation between the two countries to defeat drug cartels that have killed thousands of people in Mexico's northern border states. The ambassador spoke in Washington days before President Barack Obama heads to Mexico to meet with President Felipe Calderon.

Mexican Ambassador Arturo Sarukhan says his government is engaged in a fierce battle with drug traffickers that export illegal narcotics to the United States, but that Mexico cannot win the battle alone. "You need two to tango [dance]. And as Mexico seeks to shut down the flow of drugs coming into the United States from Mexico and South America, we need the support of the United States to shut down the flow of weapons and bulk cash [into Mexico]," he said.

The Obama administration has boosted the number of federal agents and augmented other resources along the U.S. border with Mexico in response to the increasing violence by drug gangs. In addition, President Obama has dispatched Secretary of State Hillary Clinton, Homeland Security Secretary Janet Napolitano and other top officials to Mexico to formulate a coordinated response to the trafficking threat. Mr. Obama has noted that the United States must reduce its appetite for illegal drugs.

Ambassador Sarukhan praised the flurry of consultations between the two countries, as well as the boost in U.S. personnel along the border. He expressed reluctance to comment on American domestic affairs, but suggested that a renewal of the now-expired U.S. ban on assault weapons would be helpful in curbing the flow of high-powered armaments to Mexican drug cartels.

"We have seen a dramatic rise [in the number] of assault weapons being seized in Mexico. There is a direct correlation between the expiration of the assault weapons ban, and our seizures of assault weapons. We cannot determine how [the U.S.] Congress and the [Obama] administration will move on this. What we will say is this is one of the instruments -- by reinstating the ban -- that could have a profound impact on the number and caliber of weapons going down to Mexico," he said.

U.S. Attorney General Eric Holder has voiced support for reinstating the assault weapons ban, which expired in 2004, saying it would be beneficial to both the United States and Mexico.

Asked about the safety of visitors to Mexico, Ambassador Sarukhan said that, while the drug war has engulfed the country's northernmost states, the rest of the Mexico is safe for visitors and tourists. He urged anyone traveling to the border cities of Tijuana and Ciudad Juarez to be cautious.

President Obama heads to Mexico City Thursday for an overnight stay before continuing to Trinidad and Tobago for the fifth Summit of the Americas. Combating border violence is expected to top discussions with Mexican President Felipe Calderon, along with trade and commercial issues and immigration concerns.

Mexicans comprise a large proportion of the more than 12 million illegal immigrants in the United States. During last year's presidential campaign, Barack Obama pledged to pursue comprehensive U.S. immigration reform. He has not spoken in detail on the issue since taking office in January.