President Trump’s “zero tolerance” policy at the United States-Mexico border, where all border crossers are criminally prosecuted, is deterring foreign nationals from entering the country illegally.

A new report by BuzzFeed News revealed how foreign nationals are now having second thoughts before traveling to the U.S.-Mexico border and crossing illegally with their children thanks to Trump’s immigration crackdown.

The policy to prosecute all illegal border crossers, including illegal alien adults who cross the border with children, results in border-crossing parents having their children taken into federal custody. This is a loophole known as the Flores Settlement Agreement. On Wednesday, Trump signed an executive order that challenges Flores and will keep adult border crossers and their children in detention together until they are deported.

Already, though, BuzzFeed reports that foreign nationals are staying put in Mexico and Central America for fear that they will be prosecuted once crossing the southern border:

Families waiting inside Mexico to cross into the US are increasingly nervous as reports of the child separations enforced under the Trump administration’s “zero tolerance policy” sow fear and anger on the other side of the border. [Emphasis added]

The four foreign families interviewed by BuzzFeed that were planning to cross into the U.S. illegally are apparently now “staying put” in Mexico.

Though border crossing numbers are yet to be in for the month of June, federal immigration officials have repeatedly said that Trump’s “zero tolerance” policy is likely to help stem the tide of surges of illegal immigration and foreign nationals using children to enter the U.S. with the hopes of eventually being released into the interior of the country.