A Guatemalan woman and her infant daughter seeking asylum sit at a Catholic Charities relief center on Sunday, June 17, 2018 in McAllen, Texas
Washington (AFP) - Democratic and Republican lawmakers upped the ante Sunday on the thorny issue of the separation of migrant children from their parents at the US border, as First Lady Melania Trump made a rare political plea to end the deeply controversial practice.
The "zero-tolerance" border security policy implemented by President Donald Trump's administration has sparked outrage on both sides of the political aisle and took on particular resonance as America celebrated Father's Day.
Trump has said he wants the separations to end, but continues to blame opposition Democrats for the crisis, which critics say is one of his own making.
His wife, who does not often wade into the political arena, did not denounce his administration's policy, but instead called for bipartisan immigration reform to fix the issue.
"Mrs Trump hates to see children separated from their families and hopes both sides of the aisle can finally come together to achieve successful immigration reform," her spokeswoman Stephanie Grisham told CNN.
"She believes we need to be a country that follows all laws, but also a country that governs with heart."
Immigration is one of the most divisive, hot-button crises plaguing the Trump administration.
During one recent six-week period, the government said nearly 2,000 minors were separated from their parents or adult guardians -- a figure that only stoked the firestorm.
The number of separations has jumped since early May, when Attorney General Jeff Sessions announced that all migrants illegally crossing the US border with Mexico would be arrested, regardless of whether the adults were seeking asylum.
Since children cannot be sent to the facilities where their parents are held, they are separated.
Some of Trump's fellow Republicans have said the policy must end.
"What the administration has decided to do is to separate children from their parents to try to send a message that if you cross the border with children, your children are going to be ripped away from you," Senator Susan Collins told CBS television's "Face the Nation" news program.
"That's traumatizing to the children who are innocent victims, and it is contrary to our values in this country."
Amid deep divisions, congressional Republicans have struggled to craft a viable immigration plan.
The Republican-led House of Representatives may vote this week on two immigration measures -- a hardline bill and a compromise measure that would limit legal immigration while also ending family separations.
After touring a processing center in McAllen, Texas on Sunday, a group of Democratic lawmakers warned of the "irreparable harm" caused by the separations, repeating a phrase used by the American Academy of Pediatrics.
"This new policy of the Trump administration... is undermining the founding values of this country," said Representative David Cicilline.
"We saw the fear in the eyes of these children who are wondering when they will see their parent ever again. It's a disgrace, it's shameful and it's un-American."