Mexico City ? U.S. Secretary of State Hillary Rodham Clinton on Wednesday pledged to stand with Mexico in its violent struggle against drug cartels and admitted that Americans’ “insatiable” appetite for illegal narcotics and their inability to control weapons smuggling was partly to blame.

Fearing that Mexican drug violence may spill across the border, Clinton promised to boost cooperation to improve security on both sides.

“The criminals and kingpins spreading violence are trying to corrode the foundations of law, order, friendship and trust between us that support our continent,” she told a news conference with Mexican Foreign Relations Secretary Patricia Espinosa. “They will fail.”

“We will stand shoulder to shoulder with you,” she said after lengthy talks with Espinosa and Mexican President Felipe Calderon.

On Tuesday, the Obama administration pledged to send more money, technology and manpower to secure the border in the U.S. Southwest and help Mexico battle the cartels.

Clinton said Wednesday the White House would also seek an additional $80 million to help Mexico buy Blackhawk helicopters.

All that is in addition to a three-year, $1.4 billion Bush administration-era program to support Mexico’s efforts. Congress already has approved $700 million of that. President Barack Obama has said he wants to revamp the initiative.

Obama said Tuesday he wanted the U.S. to do more to prevent guns and cash from illicit drug sales from flowing into Mexico.

But Clinton’s remarks were more forceful in recognizing the U.S. share of the blame. In the past, particularly under the Bush administration, Mexican officials have complained that Washington failed to acknowledge the extent that U.S. drug demand and weapons smuggling fuels the violence.