MEXICO CITY - In his second big trip abroad since becoming U.S. president, Barack Obama pledged strong support on Thursday for the Mexican government's fight against powerful drug cartels, who are waging turf wars along the border.

Obama, who made his first major foray onto the international stage in Europe earlier this month, offered Mexican President Felipe Calderon a partnership in his efforts to combat drug gangs.

At a time when the Mexican government has so courageously taken on the drug cartels that have plagued both sides of the borders. It is absolutely critical that the United States joins as a full partner in dealing with this issue, Obama said at a welcoming ceremony.

White House officials have played up the symbolism of Obama's visit to Mexico, which is struggling to contain unprecedented drug gang violence that is spilling over into the United States.

I think that President Calderon has done an outstanding and heroic job in dealing with what is a big problem right now along the borders with the drug cartels. Obama said on CNN's Spanish-language channel.

Obama is also expected to discuss energy and the economy with Calderon in Mexico City before heading to Trinidad and Tobago for the Summit of the Americas on Friday.

Obama hopes to improve relations with Mexico and the rest of Latin America after a deterioration in relations his advisors blame on former President George W. Bush.

MORE DRUG VIOLENCE

On Wednesday, about a dozen people died in a shootout between troops and suspected drug traffickers in southern Mexico, typical of the clashes that killed 6,300 people across the country last year.

But Calderon told NBC's Today show that he was absolutely not losing the war on drugs.

Obama will push the U.S. Senate to ratify a treaty designed to reduce the flow of arms and ammunition to drug cartels in Latin America, a senior U.S. official said.

The Obama administration is tightening security at the U.S.-Mexico border to prevent trafficking of guns from the United States to Mexican cartels and hopes to send Black Hawk helicopters to bolster Calderon's effort.

Obama's outreach to Mexico has already included a visit by Secretary of State Hillary Clinton, who soothed Mexicans by acknowledging the violence there stemmed partly from Americans' insatiable demand for drugs.

Obama wrote in an op-ed article sent to a handful of Latin American newspapers that his efforts to help wipe out organized crime would start at home -- reducing U.S. demand for illegal drugs and stemming the flow of arms and cash over the Mexican border.

Homeland Security Secretary Janet Napolitano on Wednesday named a border czar, Alan Bersin, a former Justice Department official who had served in a similar role under former President Bill Clinton. She said his mission was to see that pledges on border security fed through to results.

George W. Bush Mexico Barack obama