A key element of Donald Trump’s zero-tolerance immigration policy has been scaled back amid a global uproar over the separation of more than 2,300 migrant families.

The move halts the practice of turning over parents to prosecutors for charges of illegally entering the country.

Customs and Border Protection Commissioner Kevin McAleenan said that Mr Trump’s order to stop splitting immigrant families at the border required a temporary halt to prosecuting parents and guardians, unless they had criminal history or the child’s welfare was in question.

He insisted the White House’s zero-tolerance policy toward illegal entry remained intact.

The separation of families has shocked the world. Credit: AP

Mr McAleenan’s comments came shortly after Attorney General Jeff Sessions defended the administration’s tactics in a speech in Nevada and asserted that many children were brought to the border by violent gang members.

Together, their remarks added to the nationwide confusion as mothers and fathers struggled to reunite families that were split up by the government and sometimes sent to different parts of the country.

Families are growing increasingly frustrated in trying to reunite with their children after weeks apart.

Addressing reporters in Texas, Mr McAleenan said he stopped sending cases of parents charged with illegally entering the country to prosecutors “within hours” after Mr Trump signed an executive order last week to cease the separations.

Mr Trump spoke at a rally South Carolina on Monday Credit: AP/Susan Walsh

The commissioner and Mr Sessions insisted that the administration’s policy remains in effect, even though immigrant parents are no longer being prosecuted under the new guidelines Mr McAleenan said he is working on a plan to resume prosecutions.

“We can work on a plan where adults who bring kids across, who violate our laws, who risk their lives at the border could be prosecuted without an extended separation from their children,” he said. “We’re looking at how to implement that now.”

White House press secretary Sarah Huckabee Sanders stressed that the administration’s reversal was only temporary because the government is running out of resources.

“We’re going to run out of space,” she said. “We’re going to run out of resources to keep people together.”

Up to 2,300 children were separated from their migrant parents from the time the policy was adopted until June 9. Credit: AP

Providing a glimpse of relief, Mr McAleenan said border apprehensions in June were trending “lower” from previous months but he declined to be more specific until numbers are released July 8.

Speaking at a school-safety conference in Reno, Mr Sessions cast the children as victims of a broken immigration system and urged Congress to act.

While hundreds of protesters rallied outside a hotel-casino, the attorney general said more than 80% of children crossing the border arrive alone, without parents or guardians.

HE said they are “often sent with a paid smuggler”.

“We can only guess how many never make it to our border during that dangerous journey,” he added.