WASHINGTON – President Joe Biden’s head of Homeland Security sparred Wednesday with members of Congress over the surge of migrants at the Southwest border, refusing to concede the situation was a crisis or even much different from what the two previous administrations faced.

Secretary Alejandro Mayorkas gave ground on two Republican points as he acknowledged the administration may not have adequately notified communities chosen to host facilities for migrant teens and children and said some people were released without being tested for COVID-19, though a new testing policy has been implemented.

But Mayorkas, who remained largely unflappable during nearly four hours of often hostile interrogation, repeatedly deflected Republicans who sought to cast the situation along the U.S.-Mexico border as out of control.

“We have a very serious challenge, and I don’t think the difficulty of that challenge can be overstated,” Mayorkas said. “We also have a plan to address it. We are executing on our plan, and we will succeed.”

It was the first high-profile immigration showdown for the new administration, which is facing political blowback as it copes with the sharp increase in migrants at the same time it attempts to undo some of former President Donald Trump’s signature actions to reduce both legal and illegal entry.

Republicans contend the rising number of people attempting to cross the Southwest border have been inspired by Biden’s early moves on immigration policy, which have included halting construction on the border wall and ending a program that forced asylum seekers to make their claims in Mexico and Central America.

“This administration’s actions have had a direct cause and effect on this humanitarian and border crisis,” said Rep. Michael McCaul, a Texas Republican.

The number of people found attempting to cross the border has been rising since April and last month surpassed 100,000, the highest level since before the pandemic and on track to hit a 20-year high.

U.S. authorities are still turning most people away under a public health order issued at the start of the COVID-19 outbreak. But the Biden administration, reversing Trump, has decided to allow unaccompanied teens and children to enter the country to pursue claims for legal residency, either through asylum or for some other reason.

That has created a strain for federal authorities. Under a court order, the minors must be removed from the custody of U.S. Customs and Border Protection within 72 hours and then moved to shelters run by the Health and Human Services Department until a relative or other approved sponsor can claim them.

Homeland Security enlisted the Federal Emergency Management Agency to set up temporary facilities for several thousand minors, a decision Republicans pointedly noted suggests a crisis.

Mayorkas refused to give ground. He noted Trump, despite his anti-immigration rhetoric and measures, faced a surge of migrants, as did former President Barack Obama. The solution, he argued, is immigration legislation, which Biden supports, as well as support for Central American countries and improvements to the asylum process.

“It is a reflection of the fact that our system is broken,” said the secretary, whose family brought him to the U.S. from Cuba as a child.

During Wednesday’s hearing before the House Homeland Security Committee, Mayorkas and some members of Congress attempted to shift the focus to nonborder issues handled by his department. Those included the rise of domestic violent extremism, which the secretary said “now poses the most lethal and persistent terrorism-related threat” to the country, and the response to the suspected Russian hack of government computer networks.

But the hearing kept coming back to the border, where the new administration’s policy is in sharp contrast to the preceding one.

Pressed on the “crisis” question, Mayorkas parried by reminding the committee of the Trump administration’s decision to forcibly separate migrant children from their families as part of a zero-tolerance campaign, prompting national outrage.

“A crisis is when a nation is willing to rip a 9-year-old child out of the hands of his or her parent and separate that family to deter future migration,” Mayorkas said. “That, to me, is a humanitarian crisis.”