A bipartisan pair of senators called for more press access to government facilities holding the rising number of unaccompanied migrant children arriving at the U.S.-Mexico border, as they described overcrowded conditions for minors who are being held days longer than legally allowed.

Sen. Shelley Moore Capito (R-W.Va.), one of four senators who accompanied Homeland Security Secretary Alejandro Mayorkas to the border, said in an interview with The Washington Post Saturday that as many as 100 migrant children were being held in a large room at one Customs and Border Protection processing center in El Paso amid the coronavirus pandemic.

More than 200 border agents have been diverted to this CBP facility to care for the children, Capito said. The children, who arrived at the southern border without a parent, are legally allowed to be held for only 72 hours in CBP custody before being transferred elsewhere. But many are there for days longer than that, she added.

“I’m very alarmed about the numbers and extremely concerned about the overstay in the facility,” said Capito, who called the circumstances “heart-rending.”

“They’ll move 50 out a night [and] have another 100 come in that night,” she said.

Sen. Chris Murphy (D-Conn.), who also went on the trip, said these are “not kids in so-called cages.”

But, he added, they are not facilities that anyone would “want your child in for more than 10 minutes.”

“You’re sleeping on thin mattresses on the floor. They are sort of bunched, you know, about six inches to a foot from each other,” Murphy said on NPR Saturday. “We’ve got to ultimately do better.”

On Twitter, Murphy added, “The desperation these kids and families are fleeing is hard to describe. The memory of that 13 yr old girl will be w me forever. So long as conditions are abysmal in places south, people will find a way to get here, no matter how high the wall is or how many border agents.”

The bipartisan delegation that traveled with Mayorkas to El Paso on Friday is likely to increase scrutiny on the Biden administration, which is struggling to manage the growing influx of children at the border overwhelming the U.S. immigration system.

Unaccompanied children and teens in CBP custody must be transferred to the care of Health and Human Services within three days, although the minors coming now are being held for days longer than that.

The attention is also coming at a time when Capitol Hill is shifting its focus to immigration policy, with the House passing legislation earlier this week that would offer legal status for young undocumented immigrants and agricultural workers already in the United States.

The House will consider other related bills in the coming weeks, as Democratic leaders begin rounding up support for President Biden’s comprehensive immigration proposal.

But Congress’s energy may soon be diverted into ensuring that the Biden administration has adequate resources to manage the challenges at the border. Murphy and Capito are the top Democrat and Republican overseeing Homeland Security Department funding in the Senate.

The White House has repeatedly deferred to DHS when pressed on access for journalists to the border facilities. But Capito said she reinforced to Mayorkas that reporters should be allowed in to view them.

“I pleaded with him to have as much transparency with us . . . but with the press as well,” Capito said.

Murphy added on NPR that he believed DHS could allow for “some additional press access” while ensuring that the identities of the young children were protected. “We want to make sure that the press has access to hold the administration accountable,” he said.

Mayorkas and the senators visited a CBP processing center and CHS Trail House, a facility contracted by Health and Human Services to shelter unaccompanied migrant children once they leave CBP custody.

The centers themselves were in good condition, Capito said, noting that snacks, water and hygienic facilities such as showers were readily available.

Yet public health issues remain a serious concern.

Once children are in HHS care, they are quarantined and tested for the coronavirus. Senators were told by officials that the positivity rate for migrant children at CHS Trail House was in the double digits, and two officials familiar with the briefing said 35 children out of more than 200 had tested positive.

The people, who spoke on the condition of anonymity to disclose figures given to senators, said that the positivity rate was only for this facility, rather than for all intake sites. As of March 3, court records show, there were a total of 241 minors in HHS’s care who had been diagnosed with the coronavirus and had been placed into medical isolation. More than 1,000 unaccompanied minors sent to HHS have tested positive for the coronavirus since the outbreak began, but most have since been released.

HHS said Saturday that officials will activate the Target Lodge Pecos North in Texas as an influx facility to handle the surge of unaccompanied minors, with space for 500 people to start, with the potential to expand to 2,000. Officials said they prefer to house minors in “hard-sided structures” but could use tent-like facilities if necessary.

Capito argued the Biden administration’s moves to unravel some Trump-era immigration efforts, such as the “remain in Mexico” policy that forced asylum seekers to await their court hearings outside U.S. soil, had contributed to the recent spike and warned that the numbers would climb even more if the president allowed other existing immigration policies to lapse.

One such measure would be the so-called “Title 42” public health directive issued by President Donald Trump that rapidly expelled migrants arriving at the border in an effort to stem the coronavirus pandemic. Though the Biden administration has kept the order in place, it has stopped doing so for unaccompanied children.

“You’re looking for deterrence; you’re looking for a reason to say we don’t have a porous border here,” Capito said.

Murphy pointed to a systematic dismantling by the previous administration of the U.S. asylum system as one of the main reasons driving the spike — citing, for instance, the suspension by Trump of the Central American Minors program.

That Obama-era initiative had allowed children with parents already in the United States to apply for asylum in their home countries in an attempt to deter minors from taking a risky and dangerous journey through Mexico and seeking safe harbor at the U.S. southern border.

The Biden administration has said it is restoring that program.

Maria Sacchetti contributed to this report.