WASHINGTON >> The Justice Department today said a judge’s order to reunite families separated at the border “makes it even more imperative” that Congress pass legislation that would enable it “to simultaneously enforce the law and keep families together.”

Otherwise, the administration says, “lawlessness at the border will continue.”

The administration was responding to a federal judge’s order Tuesday that U.S. border authorities must reunite separated families within 30 days. If the children are younger than 5, they must be reunited with families within 14 days of the order.

The order poses logistical problems for the administration and its “zero tolerance” policy on illegal border crossings. That policy resulted in more than 2,000 children separated from their families in recent weeks, according to the government, and placed in government-contracted shelters while the adults are detained.

U.S. District Judge Dana Sabraw in San Diego, an appointee of President George W. Bush, issued a nationwide injunction on future family separations, unless the parent is deemed unfit or doesn’t want to be with the child. The judge’s order also requires the government to provide phone contact between parents and their children within 10 days.

Trump had already signed an order ending family separations and said families would be detained together. But Sabraw’s order forces the administration to adhere to a timeline and quickly address families affected by the hardline policy embraced earlier this spring.

Health and Human Services, which takes charge of the children, referred questions to the Justice Department.

“Last night’s court decision makes it even more imperative that Congress finally act to give federal law enforcement the ability to simultaneously enforce the law and keep families together,” wrote the Justice Department in a statement.

“Without this action by Congress, lawlessness at the border will continue, which will only lead to predictable results—more heroin and fentanyl pushed by Mexican cartels plaguing our communities, a surge in MS-13 gang members, and an increase in the number of human trafficking prosecutions.”

Both chambers of Congress are working on legislation aimed at ending separation of migrant families, but there’s not been agreement on including a specific timetable in the legislation.

But it’s unclear how legislation might enable Attorney General Jeff Sessions to continue the zero-tolerance policy without separating families or placing children in jail-like settings. The Obama administration at one point tried housing families in special detention centers while immigration judges reviewed their cases. But after a federal judge ruled the arrangement violated a long-standing agreement barring kids from jail-like settings, even with their parents. The government then began releasing families into the U.S. pending notification of their next court date — a policy Sessions and Trump have derided as “catch and release.”

It’s not clear how border authorities will meet the latest deadline. Health and Human Services Secretary Alex Azar told Congress on Tuesday that his department still has custody of 2,047 immigrant children separated from their parents at the border. That is only six fewer children than the number in HHS custody as of last Wednesday.