Department of Homeland Security Secretary Kirstjen Nielsen said Wednesday that Immigration and Customs Enforcement (ICE) has to give every migrant girl over the age of 10 a pregnancy test when they cross the border.

Nielsen testified before the House Homeland Security Committee on the ongoing crisis at the border, telling Congress it was a "humanitarian catastrophe" and border officials were on track to encounter nearly one million illegal aliens this year.

Nielsen said the volume of unaccompanied children sent on a "very, very dangerous journey" was part of the humanitarian crisis at the country's southern border. Under the law, Nielsen said the United States could not directly send illegal immigrant children back to their home countries unless they were from Mexico or Canada.

"We don't want the smugglers to be able to convince parents to send their children on this perilous journey where they are absolutely victims of violence and abused," Nielsen said.

"Very unfortunately, because of the increase in violence, at ICE, when we have families with children, we have to give every girl a pregnancy test over 10. This is not a safe journey. So, I ask again that we change the law, we treat all children the same, and we afford them the opportunity to go back home if they have now legal right to be in the United States," she added.

The majority—68.3 percent—of migrants and refugees "entering Mexico reported being victims of violence during their transit toward the United States," CNN reported, citing data from Doctors Without Borders. Nearly one-third of women said they had been sexually abused, according to the same report.

Nielsen backed President Donald Trump's declaration of an emergency at the southern border after he failed to get adequate funding for a long-promised border wall. She also mirrored her boss in pushing for a merit-based immigration system.

Nielsen could not say how many migrant children were in U.S. custody, and she also couldn't give an exact figure on the amount of drugs coming across the border, although she said the figure was up.