Illegal arrivals at the U.S. southern border are set to hit one million by the end of fiscal year 2019, Department of Homeland Security (DHS) Secretary Kirstjen Nielsen told Congress in prepared remarks Wednesday morning.

“The agency is now on track to apprehend more migrants crossing illegally in the first six months of this fiscal year than the entirety of FY17, and at the current pace we are on track to encounter close to one million illegal aliens at our southern border this year,” Nielsen said.

Nielsen’s testimony comes just one day after Customs and Border Patrol revealed that in February U.S. authorities apprehended or detained 75,000 illegal aliens constituting a 30 percent increase in illegal encounters or apprehensions over the previous month. Nielsen warned that “I can report today that CBP is forecasting the problem will get even worse this spring.”

Nielsen stressed that the capabilities of U.S. authorities are becoming stretched because of the unique nature of the situation. The vast majority of new arrivals at the border constitute family units from Central America claiming asylum. (RELATED: Another Democratic Governor Is Pulling National Guard Troops From The Border)

U.S. officials say these families claim asylum to exploit loopholes in U.S. law that allow family units to be released into the interior of the country to await an appearance before an immigration judge.

“While many of them initially claim asylum and are let into the United States, only one in ten are ultimately granted asylum by an immigration judge. Unfortunately, when it comes time to remove the other 90 percent, they have often disappeared into the interior of our country,” Nielsen explained.

The DHS secretary’s testimony is intended to bolster President Donald Trump’s declaration that the situation on the southern border is a humanitarian crisis. Trump declared a national emergency at the border in mid-February which enables him to access military construction funds in order to begin building his proposed border wall.

Trump, however, is likely to face backlash within his own party after the House of Representatives passed a disapproval resolution of his national emergency. Four Republican senators said they will join their Democratic colleagues in voting for the resolution, setting up a situation where Trump may have to issue his first presidential veto.