"The United States will not be a migrant camp or a refugee holding camp", he said.
President Trump on Monday tweeted a challenge to Democrats, saying they should back GOP immigration bills aimed at fixing "the world's worst immigration laws".
The families were all separated so the parents could be criminally prosecuted, said a spokesman for the Department of Homeland Security, who declined to be named, on a call with Reuters.
Many politicians in Donald Trump's party support his government's actions but other politicians both in his party and in other parties, are preparing a new law which would end the separation of children and parents at the border. Her spokeswoman says that Mrs. Trump believes "we need to be a country that follows all laws", but also one "that governs with heart".
The Former First Lady concluded her argument by urging for a "more compassionate" and "more moral" answer to the current crisis.
Since children can not be sent to the facilities where their parents are held, they are separated, which the American Academy of Pediatrics has warned causes "irreparable harm" to the children.
Trump's legal team emboldened by inspector general report
The FBI obtained a warrant nine days before the presidential election to review those emails, found on the laptop of former Rep. That investigation, now led by Mueller, is also looking into whether Trump obstructed justice.
Former Trump adviser Anthony Scaramucci said in a weekend interview that the child separation interview could be unsafe for Trump.
Trump was due to meet Republicans in the House of Representatives on Tuesday as they prepared to vote on two immigration bills.
But the recent wave of children being taken from their families on the United States border with Mexico has provoked widespread outrage, including from some Republicans.
"If we are truly that country, then it is our obligation to reunite these detained children with their parents", she wrote.
He has blamed Democrats for the impasse, even though his fellow Republicans control both chambers of Congress.
Her spokeswoman, Stephanie Grisham, said Mrs Trump "hates to see children separated from their families" and believes the U.S. should be a country that "governs with heart".
Through the end of May, nearly 2,000 children were separated from adults who said they were their parents or guardians, the department said last week. They said a pilot program under Mr. Obama showed that was effective in getting people to show up for their court dates. She repeats the digits and announces, through tears: "My mommy says that I'll go with my aunt, and that she'll come to pick me up there as quickly as possible".