Mexico City  - Mexican President Felipe Calderon saluted Friday the "constructive attitude" of the new US administration in the fight against drug gangs.

As he hosted US Homeland Security Secretary Janet Napolitano and US Attorney General Eric Holder in Mexico City, however, Calderon also expressed his "concern" over the fate of millions of Mexicans who live and work illegally in the United States.

Mexico's Foreign Ministry said that an agreement was reached with Napolitano to create a High-Level Taskforce on Migration to look for more efficient ways to deal with the phenomenon.

"The group is set to evaluate and formulate public policy on issues such as facilitating legal migration, protecting the rights of migrants, proceeding for repatriation and informing the population about the risks of crossing the border without suitable documents, among others," the ministry said.

Napolitano, who attended a forum on the illegal traffic of weapons in the Mexican town of Jiutepec, said Thursday that her country would launch measures to punish employers who hire illegal migrants, particularly in agriculture.

Calderon was said to have "acknowledged the constructive attitude shown by the government of President [Barack] Obama to strengthen border security and tackle the problem of organized crime, under the principle of shared responsibility," the Mexican presidency noted.

In 2008, more than 6,300 murders in Mexico were blamed on drug cartel conflicts, including the deaths of more than 500 police and military units.

Calderon has deployed 45,000 army troops to combat the scourge, and cities like Juarez, near the US-Mexico border, are under martial law.

Holder's high-profile meeting with Calderon underlined the efforts of the Obama administration to get on good terms with the US' southern neighbour after years of soured relations.

Obama himself is to visit Mexico on April 16-17 on his way to the Americas summit in Trinidad and Tobago.

US Secretary of State Hillary Rodham Clinton, on a visit to Mexico last week, made the first-ever public admission by the US that it must accept part of the blame, for the drug-related violence that is ravaging Mexico, because of the "insatiable demand" for illegal drugs in the US.

Also last week, Washington launched a major new effort to crack down on the cartels by beefing up drug and weapons agents along the border and sending help into Mexico in the form of trainers for the justice system and equipment such as helicopters.

Mexican cartels are major suppliers of methamphetamine, cocaine and heroin to the US.

More than 90 per cent of guns used in violent crimes in Mexico are brought in illegally from the United States, the US Bureau of Alcohol, Tobacco, Firearms and Explosives says. (dpa)