MONTERREY, Mexico – U.S. lawmakers will review the language of an anti-drug plan that Mexican officials contend infringes on their nation's sovereignty by conditioning aid to performance on human rights, a senior U.S. senator said Sunday.

Sen. Christopher Dodd, D-Conn., said that a visiting delegation of U.S. lawmakers will take concerns expressed to them by Mexican legislators this weekend back to the U.S. Congress, which has been considering the aid plan, known as the Merida Initiative.

The plan, proposed in October by U.S. President George Bush, would give Mexico and other Latin American countries US$1.4 billion over several years to fight drug trafficking.

But Mexican lawmakers object to several conditions, including performance evaluations, reviews of how the money was spent and guarantees that civilian investigators would be allowed to look into allegations of abuse by Mexico's military.

“We heard from everyone here the common message that this language has got to be changed,” said Dodd, one of 11 U.S. legislators attending a two-day meeting with their Mexican counterparts in Monterrey.

“Our friends in Mexico needed to vent and explain how this issue was not handled well,” the senator added. “Anything that smacks of certification is a nonstarter.”

Ruth Zavaleta, speaker of Mexico's lower house of congress, said the chamber would refuse any conditions on U.S. aid and welcomed Dodd's promise to review the plan.

“There is a commitment to take our concerns and discuss them in the U.S. Congress, and we hope that they can correct (the plan) with the demands we are making,” Zavaleta said.

Democratic Sen. Patrick Leahy, chairman of the U.S. Senate subcommittee that oversees State Department and international program funding, has defended conditioning the aid. He sent a letter to Sunday's meeting underlining U.S. commitment to the plan.

“We recognize the responsibility of the United States as the primary market for illegal drugs and the source of most of the guns used by the Mexican cartels,” Leahy said in the letter.

“I am confident that in the final version of the Supplemental the Congress will provide support for the Merida Initiative in a manner that addresses our shared interests and concerns,” Leahy said.

Mexican President Felipe Calderón has earned Washington's support for a crackdown on powerful drug cartels by more than 25,000 troops. But violence has surged as cartels respond with brazen attacks against security forces.

Calderón's government has pledged to wait for a final version of the U.S. bill before deciding whether to accept the aid.

The lawmakers also agreed to establish a binational working group to discuss immigration reform.