A new report from the advocacy group Human Rights Watch says policies in the United States and other countries have led to a sharp rise in activity along a dangerous border crossing between South and Central America.

The Darien Gap is a dense, roadless jungle between Panama and Colombia. Tyler Mattiace is an Americas researcher Human Rights Watch who co-authored says several years ago, only a few thousand people would make the trek through it. But over the last 12 months, more than half a million people have crossed the gap, where they face attacks from armed groups, a lack of food and water and wild animals.

"Many people are making this journey because other safer ways of trying to migrate — usually to the United States, but sometimes to other places in the Americas — have been closed off to them by a series of policies that are aimed at trying to prevent people from migrating."

At the behest of the U.S., Mattiace says Latin American countries have imposed travel restrictions, like new visa requirements in Mexico for some nationalities, that make it more difficult for migrants to travel by plane en route to the U.S.-Mexico border. He says just like deterrence-based policies at the U.S.-Mexico border, those imposed further from that border don’t actually slow migration, they just make it more deadly.

"Many people who would have previously maybe flown to Mexico and then try to find a way to cross the border from there are now making this journey by land, which is one of the big factors that led to this increase in people traveling through the Darien Gap," he said "But I think the important point here is really to think about how these kinds of policies we see again and again — trying to prevent migration through deterrence — rarely reduce the number of people who are migrating. What it often does do is drive people to more dangerous places um where they're putting their lives at risk."

Panamanian data collected by the Washington Office on Latin America shows September being the second busiest month on record for migration through the Darien Gap, with more than 70,000 people traveling through.