What's next for children already separated from their families? It's unclear how parents and children will be reunited.

Amid the Trump administration's crackdown on illegal immigration, thousands of children were separated from their families, while parents were prosecuted under a "zero-tolerance" policy.

On Wednesday afternoon, Donald Trump signed an executive order that he said would keep immigrant families at the border together "while ensuring we have a powerful, very strong border."

From May, when the policy was enacted, through June 9, almost 2,300 children have been separated from their parents, according to the Department of Homeland Security. Those children have been placed in the custody of the Office of Refugee Resettlement under the Department of Health and Human Services, which manages care for unaccompanied minors.

Despite the new executive order, it's unclear when or how those children will be returned to their parents.

'Still very early'

"It is still very early and we are awaiting further guidance on the matter," Brian Marriott, a spokesman at the Administration for Children and Families, a division of the Department and Health and Human Services, said in a statement late Wednesday. "Our focus is on continuing to provide quality services and care to the minors in HHS/ORR funded facilities and reunifying minors with a relative or appropriate sponsor as we have done since HHS inherited the program."

Under the current process, HHS works "expeditiously" to place children in care of a sponsor, although there is no time limit in "terms of days," said Steve Wagner, an acting assistant secretary at HHS.

The president faced mounting pressure from advocacy groups, lawmakers, foreign governments and even family members to end the policy separating families at the border. Images of the children shown to him by his daughter, Ivanka, are said to have helped sway him.

Advocates slammed Trump's executive order, saying it ended the separation of families only to require that DHS jail children along with their parents while criminal prosecutions proceeded.

'It was barbaric'

"We're not fooled by this bait and switch," said Archi Pyati, chief of policy at Tahirih Justice Center. "It was barbaric to separate children from their parents. Family detention is also inhumane and harmful to children. Prison is no place for kids."

As of earlier this week, there were 11,786 children in HHS custody -- both children separated from their parents and unaccompanied minors that illegally crossed the border alone.

In recent weeks, HHS opened facilities containing temporary, tent-like structures in Florida and Texas to deal with the influx of children.

"They are under constant supervision and observation to address any health or medical concerns while they are in our care," Wagner said.

57 days

The average stay in custody for an unaccompanied minor is 57 days.

There is no official policy for keeping parents in Immigration and Customs Enforcement custody informed of where their children are, other than a 2017 directive, which provides guidance regarding undocumented parents "who have a direct interest in family court or child welfare proceedings in the United States."

Once a parent is prosecuted and the child is placed in HHS custody, ICE "will make every effort to reunite the child with the parent once the parent’s immigration case has been adjudicated," a spokesperson for ICE said before the executive order was signed.

"ICE is committed to connecting family members as quickly as possible after separation so that parents know the location of their children," the spokesperson added.

The executive order does not overturn the administration's "zero-tolerance" policy, as Trump said during the Oval Office signing, but rather allows the Department of Homeland Security to maintain custody of undocumented families pending immigration proceedings.

The order also said DHS can construct new housing facilities. There are currently three family detention facilities -- one in Pennsylvania and two in Texas. As of June 4, the total population of the facilities was around 2,600. ICE said it does not disclose capacity of those facilities because it is proprietary information held by the contractors.

20 days

Now, under what's called the Flores consent decree, children can be detained by ICE for only 20 days. The president will instruct the Department of Justice to challenge that decree and not abide by it while it is being challenged, a source told ABC Chief White House Correspondent Jonathan Karl.

"It's certainly the case that right now we have the lawful authority to detain a family unit for up to 20 days," said Gene Hamilton, counselor to Attorney General Jeff Sessions.

He referred questions about family reunification to HHS and DHS.

On May 7, Sessions discussed the "zero-tolerance" policy for illegal entry on the southwest border.

"If you cross this border unlawfully, then we will prosecute you," he said. "If you are smuggling a child, then we will prosecute you and that child will be separated from you as required by law."

The attorney general directed the department to prosecute all illegal crossings. Most adults usually get a short jail sentence. But while parents served their time in jail, their children were forced into government custody because they couldn't be jailed.

That led to confusion and difficulty for parents as they tried to reunite with their children, who in some cases were sent across the country.

'It's a terrible thing'

"It's a terrible thing, the experience we've had," Jocelyn, who was separated from her son for months, told ABC News.

Jocelyn was in U.S. federal criminal custody for almost a month for her misdemeanor charge of entering the country illegally and then spent another six months in detention facilities. She was living in a West Texas shelter, while her son, James, was sent to center in Chicago.

They were only recently reunited.

ABC News' Tom Llamas, Lauren Pearle and Meridith McGraw contributed to this story.