LONG BEACH, Calif. (AP) — A federal emergency shelter in California is starting to receive immigrant children from border facilities in what advocates hope will be an improvement in their care.

As many as 150 children were expected Thursday at the Long Beach Convention Center at the latest in a series of sites set up across the country following a rise in the number of immigrant children stopped alone on the Mexico border, the Department of Health and Human Services said.

After border facilities grew crowded with children who said they had not been given showers for days, the department started opening large-scale temporary shelters to house these minors until they can be released to relatives who can care for them in the U.S.

The center in Long Beach is expected to be able to hold up to 1,000 children. Officials were given a tour of the site, which had books, stuffed animals and backpacks laid out on cots and butterfly decorations displayed on the walls. There was a recreation area with soccer nets, board games and large screens to watch movies.

Children will receive three or four hours of daily classroom time and get to play outdoors. They are expected to be released to family on average in a week to 10 days, Mayor Robert Garcia said. He added that he was told by federal officials that the site could prove to be a model for how to make the shelters as welcoming as possible.

“It looks like a place where children can be,” Angelica Salas, executive director of the Coalition for Humane Immigrant Rights, told reporters after the tour.

With more than 20,000 immigrant children currently in government custody, U.S. officials have been scrambling to open such facilities.

The government failed to prepare for an increase in mostly Central American children traveling alone as President Joe Biden ended some of his predecessor's hardline immigration policies. The Biden administration decided against quickly expelling unaccompanied minors from the country as the Trump administration had done for eight months.

Children are initially taken to border facilities that aren't equipped to house them for long periods of time. From there, they are being sent to these shelters while case workers assess which relatives are suitable to take them.

The minors will then go through immigration court proceedings to see whether they are eligible to stay in the U.S. or must return to their home countries.

The site in Long Beach is being operated by DRC, a disaster management company, and expected to mostly house girls, said Bonnie Preston, acting regional director for Health and Human Services. She said she could not immediately say how much it would cost to operate the site.

“We're really in an emergency situation," she said. "The budgets are, you know, rolling out as we see what the need is, and the budget will meet the need to keep the children safe.”

Lindsay Toczylowski​​, executive director of Immigrant Defenders Law Center, said she was pleased the shelter had already been equipped with workspace for attorneys to come in and meet with children to explain how the U.S. immigration system works and discuss their legal cases. She said it was clear efforts were taken to make the large site feel comfortable for children, but hopefully they will only be there a very short time.

“This will be a safe place for kids to be, but it should be temporary,” she said.