US First Lady Melania Trump has spoken out on the policy of separating parents and children illegally entering the country from Mexico.
Mrs Trump "believes we need to be a country that follows all laws, but also a country that governs with heart," her spokeswoman said.
Her comments follow growing controversy over President Donald Trump's "zero-tolerance" policy.
In a recent six-week period there were nearly 2,000 family separations.
Adults who try to cross the border, many planning to seek asylum, are placed in custody and face criminal prosecution for illegal entry.
As a result, hundreds of minors are now being housed in detention centres, and kept away from their parents - a policy which rights groups have criticised as unprecedented.
In her rare intervention, Mrs Trump said she "hates to see children separated from their families and hopes both sides of the aisle [Republicans and Democrats in Congress] can finally come together to achieve successful immigration reform".
Mr Trump has blamed a law "Democrats gave us" for the policy, but it is unclear which law he is referring to.
In a tweet on Saturday he urged Democrats to work with Republicans to create new legislation.
However, critics have pointed out that detaining children separately from their parents was a policy announced by US Attorney General Jeff Sessions last month and does not require congressional action to be stopped.
The policy has divided Republicans, with its defenders pointing out that children are routinely taken from parents accused of crimes.
The additional child detentions - reportedly including babies and toddlers - have resulted in some shelters and foster homes reporting that they are running out of space.
On Sunday, Democratic members of Congress paid a "surprise Father's Day visit" to an Immigration and Customs Enforcement (ICE) detention centre in New Jersey, demanding to see detainees separated from their children.
Meanwhile, officials announced plans to erect tent cities to hold hundreds more children in the Texas desert where temperatures regularly reach 40C (105F).
Local lawmaker Jose Rodriguez described the plan as "totally inhumane" and "outrageous", adding: "It should be condemned by anyone who has a moral sense of responsibility."
Protesters marched to one such tent city in Tornillo, Texas, on Sunday where hundreds of children were being held without their parents.
In the first two weeks of the "zero-tolerance" approach, 658 minors - including many babies and toddlers - were separated from the adults that travelled with them, according to US border officials.
But the practice was reportedly happening before that with more than 700 families affected between October 2017 and this April.
In many of the cases, the families have been reunited after the parent was released from detention. However, there are reports of people being kept apart for weeks and even months.
Family separations had been reported in previous administrations but activists say the numbers then were very small.