Kirstjen Nielsen: “Please do not take this dangerous journey. It is dangerous to you. It is dangerous to your children.”

First and foremost, border security is national security.

We do not have a policy of separating families at the border. Period.

It was the Russians. We know that. They know that. It was directed from the highest levels. And we cannot and will not allow that to happen again.

So if a migrant comes to a port of entry, they haven't broken any laws.