The American Civil Liberties Union (ACLU), which sued the government over its separation policies, questioned that assertion.
Looking for news you can trust?
Following Thursday's announcement, the administration faces another deadline July 26 to reunite the remainder of the more than 2,000 children who remain separated from their families.
The government, which is under court order to reunite thousands of children separated from their parents under its "zero-tolerance" policy, said 57 had been reunited as of 7 a.m. (1200 GMT) on Thursday.
As the government awaits the court's Monday decision on whether or not the timeline for family reunification will be extended, time is of the essence: doctors have repeatedly warned that being separated from parents for even short periods of time can cause symptoms of toxic stress in children, which can derail healthy emotional development. A few months after announcing that his administration would undertake a "zero tolerance" policy that took children from their parents, Trump was forced to back away from the policy after drawing global outrage. Immigration attorneys say they already are seeing barriers to those reunifications from a backlog in the processing of fingerprinting of parents to families unable to afford the airfare to fly the child to them - which could run as high as $1,000. Administration lawyers said just four children had been reunited with their families, and 51 children were eligible for reunification with a parent.
Still, 22 other children were deemed unsuitable for reunification due to safety concerns posed by the adults the children would be returned to, including 11 who have serious criminal histories, according to the administration.
In a call with reporters, DHS's Matthew Albence said the 12 adults who have already been deported had an opportunity to take their children with them, but declined.
Almost two weeks after a judge ordered officials to reunite the families they'd split up, we only have a handful of anecdotal examples of kids and parents being brought back together.More news: Rakitic had a fever the day before England semi-final
The Latest on court-ordered deadlines for the government to reunite children and parents who were separated at the border. The DoJ has not provided any more information on the family.
"The reunification process has been chaotic and has unequivocally come at a cost", Beth Krause, a supervising lawyer at the Legal Aid Society's Immigrant Youth Project, said in a statement. "Eliminating any one of these steps will endanger children". One parent was from Honduras and the other from El Salvador.
"Our agencies' careful vetting procedures helped prevent the reunification of children with an alleged murderer, an adult convicted of child cruelty, and adults determined not to be the parent of the child", they added.
Seven adults were not parents of the children from whom they were separated. In many cases, the problem was simple if shocking: the government was ready to release the children but couldn't yet verify with whom they belonged.
"But until I have both my children with me, I don't know what I will do", she said.
Donald Trump's administration has said it will release some migrant families from detention with ankle monitors, marking a return to the so-called "catch-and-release" policy the president vehemently denounced.
The Trump administration was left with few options after a series of court orders.
Government officials touted the screening process for parents, including background checks and DNA tests.
Also on Thursday, the government will update Sabraw on the number of children that still must be reunited with and whether the government expects to meet the Jul 26 deadline. They are to reunite more than 2,000 older children with their families.