HOUSTON (CN) — With record numbers of asylum-seeking youths entering the country, Texas Governor Greg Abbott is demanding a shelter for them in San Antonio be closed amid reports of sexual abuse.

Nearly 19,000 children traveling alone crossed the Mexico border and turned themselves in to Border Patrol agents in March, more than double the 9,271 who did so in February, according to stats released Thursday by U.S. Customs and Border Protection.

That is the most Border Patrol apprehensions of unaccompanied children since CBP started publicizing numbers on the demographic in 2009.

Republicans are accusing President Joe Biden of creating a crisis by letting youths enter without parents, some as young as 3, and allowing some families to stay in the U.S. as they await adjudication of their asylum claims.

Biden partly reversed a policy of former President Donald Trump of immediately expelling nearly all people who enter the country illegally due to purported concerns they could spread Covid-19.

But Biden is still using it to turn back single adults at the Southwest border.

In total, the Border Patrol picked up 168,195 immigrants on the border in March, including 96,628 single adults and 52,904 family units, its busiest month for arrests since March 2001, according to the Associated Press. However, experts say the current numbers are being inflated by people who have been expelled and return only to be expelled again.

The Biden administration has opened eight emergency shelters for immigrant children in Texas and one of them came under fire Wednesday from Governor Abbott.

After two Texas agencies received reports early Wednesday that some of the 1,370 teens housed by the federal government at the Freeman Coliseum in San Antonio had been sexually abused, Abbott expressed outrage at a press conference outside the coliseum Wednesday afternoon.

“This facility is a health and safety nightmare,” he said.

Though the Republican governor acknowledged he had yet not been inside the coliseum to inspect the conditions for himself, and he did not know who the whistleblowers were, he said the shelter was short-staffed, underfeeding youths and not separating those infected with Covid-19 from healthy ones, and he feared more than one had been sexually assaulted.

“This facility should be shut down immediately. The children should be moved to better staffed and better secured locations,” Abbott said.

He said the Texas Rangers are investigating three allegations of abuse or neglect at the site, which he toured after the press conference alongside Bexar County Commissioner Rebeca Clay-Flores.

Clay-Flores, a Democrat, told reporters Wednesday she had been in the shelter multiple times and the teens are offered three meals and two snacks a day, and anyone who tests positive for Covid-19 is separated far from others.

“What I saw when I went in there on several occasions, it was well-staffed, the children are very happy and very excited to be here,” she said.

Republican Texas U.S. Senator John Cornyn has asked the inspector general of the U.S. Department of Health and Human Services, which is housing around 16,000 immigrant youth in its shelters across the country, to investigate the claims of abuse at the San Antonio shelter.

The Biden administration is scrambling to transfer arriving children to these shelters from Border Patrol stations, where they are supposed to be held for no more than three days.

But the White House is struggling to abide by this standard, in particular at a CBP tent complex in Donna, Texas.

Though the site is meant for no more than 250 detainees, more than 4,000 people are being held there, jammed together at night, sleeping on mats under foil blankets, the Associated Press reported.

Border Patrol stations and HHS shelters have received several visits this year from separate groups of Republican and Democratic lawmakers.

Cornyn said he has toured four Texas shelters for immigrant youths and plans to visit another in Dallas this week.

Republicans are demanding Biden do something to stop immigrants from crossing into the U.S., blaming him for ending a Trump-era policy of forcing immigrants to stay in Mexico to await decisions on their asylum claims.

Democrats meanwhile are accusing Republicans of engaging in political opportunism, noting they did not have the same level of concern when large numbers of immigrants were entering the country in 2019 with Trump office.