U.S. President Donald Trump wants to deport millions of illegal immigrants back to Latin America, at a time when the region is already struggling to address the highest rates of violence in the world, according to a landmark new study.

The report, the first to measure the economic cost of crime and violence in 17 Latin American and Caribbean countries, found these ills cost the region twice as much as they do countries in the developed world.

“Latin America is the most violent region in the world outside of war zones,” noted the report, released this month by the Inter-American Development Bank.

Crime-related costs in the region total $342 billion a year, a figure that is equivalent to 3.5 per cent of its gross domestic product. That is the same as what is spent on infrastructure, and six times more than Mexico and Brazil direct to social programs.

Mexico has already expressed outrage over Trump’s pledge to deport non-Mexicans in the U.S. to Mexico, calling the plan “hostile and unacceptable.” The country is not prepared to absorb an influx of Mexicans who haven’t lived there in decades, much less deal with a surge of foreigners, said Mexico’s foreign minister, Luis Videgaray, said at a joint press conference with U.S. officials on Thursday.

Also that day, Trump said his plan would focus on deporting serious criminals: “We are getting gang lords out, drug lords out,” he said. “We are getting bad dudes out of this country at a rate we’ve never seen before.”

Trump’s approach to immigration could further destabilize the region, and create difficulties for U.S. border state communities, said Ben Raderstorf, an analyst at the Inter-American Dialogue.

“If relations sour between the U.S. and Mexico, that could put at risk counter-terrorist efforts, counter-narcotics, arms trafficking and other security issues,” he said. “U.S. policies should work to support citizen security in Latin America, not undermine it because that is in the interests of everyone in the region.”