Trump administration officials say the U.S. government knows the location of all children in its custody after separating them from their families at the border and is working to reunite them.

A fact sheet on "zero-tolerance prosecution and family reunification" released Saturday night by the Department of Homeland Security also says a parent must request that their child be deported with them. In the past, the agency says, many parents have elected to be deported without their children. That may be a reflection of violence or persecution they face in their home countries.

As part of the effort, Immigration and Customs Enforcement officials have posted notices in all its facilities advising detained parents who are trying to find or communicate with their children to call a hotline staffed 8 a.m. to 8 p.m. Monday through Friday.

A parent or guardian trying to determine if a child is in the custody of HHS should contact the Office of Refugee Resettlement National Call Center at 1-800-203-7001, or via email information@ORRNCC.com. Information will be collected and sent to HHS funded facility where minor is located.

The fact sheet doesn't state how long it might take to reunite families. The Port Isabel Service Processing Center in Texas 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 the families are first stopped by Customs and Border Patrol, with children taken into custody by HHS and adults detained through ICE. Children have been sent to shelters around the country, raising alarm that parents might never know where their children can be found.

The fact sheet states that ICE has implemented an identification mechanism to ensure on-going tracking of linked family members throughout the detention and removal process; designated detention locations for separated parents and will enhance current processes to ensure communication with children in HHS custody; worked closely with foreign consulates to ensure that travel documents are issued for both the parent and child at time of removal; and coordinated with HHS for the reuniting of the child prior to the parents' departure from the U.S.

President Donald Trump on Wednesday ordered the practice of separating parents and their children to stop. As of last Wednesday, 2,053 minors who were separated at the border were being cared for in HHS-funded facilities, the fact sheet said.

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