The US must keep to pledges to tackle the flow of arms from the US into Mexico and money-laundering, Mexico's attorney general has stressed.
President Bush is trying to fund an anti-drugs initiative with Mexico
Eduardo Medina Mora said those parts of a new bilateral initiative were more important than the provision of $1.4bn of US funds under the plan.
Mr Medina also estimated about $10bn (£4.8bn) in laundered Mexican drug money ended up in US banks each year.
The anti-drugs "Merida Initiative" has caused some controversy in Mexico.
Some politicians have dubbed it "Plan Mexico", inviting comparisons with the contentious anti-narcotic scheme Plan Colombia, established by the US in co-operation with Colombia in 2000.
But President Felipe Calderon, who worked on the Merida Initiative with US President George W Bush, insists it will not entail an increased US military presence in Mexico as some suspect.
President Bush recently asked the US Congress for a first tranche of £500m funding for the plan.
The money will go towards training Mexican troops and the purchase of equipment and technology to fight the often violent drugs trade.
But on Tuesday, Mr Medina said that key parts of the agreement were US commitments to clamp down on the trade in arms and the illegal chemicals used to process drugs, money-laundering and domestic consumption of drugs.
"For me, it is far more important that the United States is dedicated to confronting these four components of the drug-trafficking equation," he told the Mexican Congress.
He said that there were some 12,000 American gun stores located close to the 3,200km border with Mexico, which, along with the US' "permissive" gun-control laws, facilitated the flow of arms into Mexico.
Mr Medina added that about $10bn of laundered Mexican drug money ended up in US banks each year. He said his office was drafting a money-laundering bill that would regulate those responsible for transactions commonly associated with money-laundering.