Trump says US policy separating migrant families is law. It's not. Donald Trump keeps saying an immigration policy is a law. It's not.

Donald Trump told reporters on Friday, when asked about separating migrant families at the U.S.-Mexico border: "I hate the children being taken away. The Democrats have to change their law. That's their law."

No, it's not. No law mandates separating families.

The administration's current policy was announced April 6 and went into effect in May. As reported by the Associated Press: "From April 19 to May 31, 1,995 children were separated from 1,940 adults, according to Homeland Security statistics."

Because of the policy, more adults have been jailed and more children have been shipped elsewhere. Previously, people who entered the country illegally and had no criminal record were detained or referred for deportation, and mothers and children usually remained together.

More from the AP: "Trump's repeated, but nonspecific references to a Democratic law appear to involve one enacted in 2008. It passed unanimously in Congress and was signed by Republican President George W. Bush. It was focused on freeing and otherwise helping children who come to the border without a parent or guardian. It does not call for family separation."

Government officials have said minors shouldn't be housed with adults in criminal holding facilities and that such a policy also should deter border crossings, even from those seeking asylum. There's a limit on how long children can be held before being transferred to a licensed family facility. More generally, the government is supposed to house minors in the least restrictive way possible.

"From a law enforcement perspective, this zero-tolerance approach makes little sense," said John Cohen, an ABC News consultant and former acting Homeland Security undersecretary. "The majority of those detained are non-violent individuals or families who have committed what amounts to a misdemeanor. Incarcerating these individuals, as opposed to issuing a notice to appear, is resource intensive, and as a result vital law enforcement resources and attention are being diverted from dealing with more serious border security issues."