He didn't release names or personal details to protect the parents' privacy, and Homeland Security officials said they needed more specifics in order to check out their cases.
A fact sheet by the Department of Homeland Security and other agencies said yesterday that authorities know the location of all children in custody after separating them from their families at the border and are working to reunite them.
It called the reunification process "well coordinated."
It also said parents must request that their child be deported with them.
In the past, the fact sheet says, many parents elected to be deported without their children. That may be a reflection of violence or persecution they face in their home countries.
It doesn't state how long it might take to reunite families.
Texas' Port Isabel Service Processing Centre has been set up as the staging ground for the families to be reunited prior to deportation.
How the Government would reunite families has been unclear because they are first stopped by US Customs and Border Patrol, with children taken into custody by the Department of Health and Human Services and adults detained through ICE, which is under the Department of Homeland Security.
Children have been sent to far-flung shelters around the country, raising alarm that parents might never know where their children can be found.
At least 2053 minors who were separated at the border were being cared for in HHS-funded facilities, the fact sheet said.
The chairman of the Senate Homeland Security Committee hedged today when pressed on whether he was confident the Trump Administration knows where all the children are and will be able to reunite them with their parents.
"That is what they're claiming," Senator Ron Johnson, (R), said on CNN.
The fact sheet states that ICE has implemented an identification mechanism to ensure ongoing tracking of linked family members throughout the detention and removal process.
Lawyers at the border have said they have been frantically trying to locate information about the children on behalf of their clients.
Garcia, the Annunciation House director, said his experience has been that telephone contact doesn't provide any information.
"If we bring in 30 cellphones, they're going to call that number, they're not going to reach 30 children," said Garcia, whose organisation has been working with federal authorities to assist immigrants for 40 years. "Actually (they're) not going to be able to give them any information on what to expect."
Customs and Border Patrol said it had reunited 522 children and that some were never taken into custody by Health and Human Services because their parents' criminal cases were processed too quickly. Officials have said as many as 2300 children had been separated from the time the policy began until June 9. It's not clear if any of the 2,000 remaining children were taken into custody after June 9.
- AP