A child embraces a woman as people protest against Trump
A child embraces a woman as people hold signs to protest against U.S. President Donald Trump's executive order to detain children crossing the southern U.S. border and separating families outside of City Hall in Los Angeles, California, U.S. June 7, 2018.REUTERS/Patrick T. Fallon

The US government has asked for more time to reunite migrant families separated at the US-Mexico border as it was revealed that the parents of some children have already been deported.

In a two-hour hearing on Friday, July 6, a government attorney said that parents of 19 children held in custody and aged below 5 had already left the US, BBC reported.

The justice department has a deadline to release these children by July 10. But it says that more time is needed to perform the required identity checks.

On Thursday, the US Department of Justice issued a formal request to Judge Dana Sabraw, a federal judge in San Diego, for relief regarding the earlier court order to release 101 children aged five and under by next Tuesday, 10 July.

The judge, who is yet to rule on the extension, said the government needed to provide a full list of those below five years of age held in custody, by Saturday afternoon, following which the original deadline would be re-evaluated.

Sabraw also said the government would need to present expectations for meeting the deadline for each child on the list to the American Civil Liberties Union, which brought the class action lawsuit.

A child is seen entering the Cayuga Center, which provides foster care and other services to immigrant children separated from their families in New York City, U.S., June 20, 2018.REUTERS/Brendan McDermid

Judge Sabraw scheduled a status hearing on Monday morning, saying he hopes an agreement can be reached regarding whether Tuesday's deadline will need to be extended. The court order also includes a deadline to release children aged between five and 17 by July 26.

Earlier this week, the US Department of Health and Human Services (HHS) stated that DNA tests on about 3,000 children will be conducted in an effort to reunite migrant families.

However, the justice department said that even while the health department was "moving expeditiously" with the tests, the process was time-consuming. It added that given the possibility of false claims, "confirming parentage is critical to ensure that children are returned to their parents, not to potential traffickers".

Protestors at anti-Trump protest in Los Angeles
Demonstrators are seen during a national day of action called "Keep Families Together" to protest the Trump administration's "Zero Tolerance" policy in Los Angeles, California, U.S. June 30, 2018.REUTERS/Monica Almeida

The government also needed to determine whether the adults had a criminal history or could pose a danger to their children, the department said.

The US government did not request a specific new set of deadlines.

More than 2,300 migrant children have been separated from their parents since early May under the Trump administration's controversial Zero Tolerance policy, which seeks to criminally prosecute anyone crossing the border illegally.