Pictures have emerged of migrant children being held in cages at a U.S. detention facility after they were separated from their parents at the border.
President Trump's 'zero tolerance' policy is being widely criticised - including by the First Lady Melania.
Reporters who toured the facility said one cage had 20 children inside.
A young girl is given some soup at a migration centre in Texas
Mr Trump's defended the policy - saying the only way is to get tough,
"The United States will not be a migrant camp, and it will not be a refugee holding facility - it won't be.
You look at what's happening in Europe, you look at what's happening in other places.
We can't allow that to happen to the United States not on my watch."
The people of Germany are turning against their leadership as migration is rocking the already tenuous Berlin coalition. Crime in Germany is way up. Big mistake made all over Europe in allowing millions of people in who have so strongly and violently changed their culture!
— Donald J. Trump (@realDonaldTrump) June 18, 2018
We don’t want what is happening with immigration in Europe to happen with us!
— Donald J. Trump (@realDonaldTrump) June 18, 2018
Children are being used by some of the worst criminals on earth as a means to enter our country. Has anyone been looking at the Crime taking place south of the border. It is historic, with some countries the most dangerous places in the world. Not going to happen in the U.S.
— Donald J. Trump (@realDonaldTrump) June 18, 2018
It is the Democrats fault for being weak and ineffective with Boarder Security and Crime. Tell them to start thinking about the people devastated by Crime coming from illegal immigration. Change the laws!
— Donald J. Trump (@realDonaldTrump) June 18, 2018