WASHINGTON (Reuters) - The U.S. State Department on Wednesday said it was working with Mexico’s government to identify the “appropriate tools” to help it tackle the threats that drug cartels pose, after President Donald Trump last week said he wanted to designate them as terrorist groups.

Trump’s announcement alarmed Mexico, which rejected it as “interventionism” and said it would respond in kind to such a move. Mexican President Andres Manuel Lopez Obrador said, for instance, that Mexico would not permit another operation like the U.S. government’s ill-fated “Fast and Furious” gun-running sting.

Designating groups as foreign terrorist organizations is aimed at disrupting their finances through the imposition of U.S. sanctions, including asset freezes and travel bans, on them and individuals and entities that support them.

Speaking at a briefing with reporters, Hugo Rodriguez, deputy assistant secretary of state for Central America, did not offer specifics on the next steps but said the U.S. agencies have been looking at this issue for months.

“What we are looking to do is put at the service of the government of Mexico any and all tools we have at our disposal to cooperate on the shared security challenge that the drug trafficking organizations pose,” he said.

“We have to work with them (Mexico) to find the tools that are going to be appropriate in the context,” he said. “If we have tools at our disposal that we can use that help contribute to addressing the DTO challenge, we’re looking at it.”

While this would not directly give the United States authority for military operations in Mexico, many Mexicans are nervous their northern neighbor could use it as a pretext for a unilateral intervention.

Lopez Obrador, who has attempted to chart a less confrontational security policy during his first year in office, reiterated he would not permit an armed foreign intervention a century after the country was last invaded, arguing that his government was already doing its part to battle criminal gangs.

Trump has repeatedly offered military assistance in the fight against drug gangs, which Lopez Obrador has always declined, even after the gangland massacre of a U.S.-Mexican family earlier this month.

U.S. Attorney General William Barr will visit Mexico on Thursday to discuss cooperation on security, Mexican Foreign Minister Marcelo Ebrard announced on Wednesday.

Barr will meet with Lopez Obrador, as well as Mexico’s own attorney general, plus the security and foreign ministers, according to the announcement.

The Mexican president has previously said his government will seek to strengthen cooperation with the United States to control the flow of “arms and dollars.”

The U.S. State Department includes dozens of organizations on its list of terrorist groups. In Latin America, left-wing guerrillas and right-wing paramilitaries, both involved in drug trafficking, have in the past appeared on the list.