AP Photo/Susan Walsh

DHS Secretary Kirstjen Nielsen and Rep. Bennie Thompson, the chairman of the House Homeland Security Committee, sparred at today's hearing over whether children are kept in "cages" at border patrol facilities.

The exchange prompted Nielsen to use her hands to show what a cage would look like.

Thompson called on Nielsen to "admit" that Customs and Border Protection uses cages, which he had seen. But Nielsen said that as children are processed, CBP uses "sub-parts" of its facilities to separate them for their safety.

Here's how the exchange unfolded:

Thompson: For the record, are we still using cages for children?

Nielsen: Sir, we don't use cages for children. In the border facilities, that you have been to, they were not made to detain children. As the children are processed through, they are in sub-parts of those facilities

Thompson: Madam, madam secretary ...

Nielsen: Yes, I'm being as clear as I can, sir. Respectfully I'm trying to answer your question.

Thompson: Just yes or now, are we still putting children in cages?

Nielsen: To my knowledge, CBP never purposefully put a child in cage, if you mean a cage like this? [Uses hands to show a cage]

Thompson: Purposefully or whatever, are we putting children in cages as of today?

Nielsen: Children are processed at the border facility stations that you have been at ...

Thompson: And I've seen the cages. I just want you to admit that the cages exist.

Nielsen: Sir, they're not cages

Thompson: What are they?

Nielsen: They are areas of the border facility that are carved out for the safety and protection of those who remain there while they are being processed. If we have two gangs, we separate them into separate areas of that facilities.

Thompson: No, no, madam secretary.

Nielsen: If we have a father and daughter, we separate (them) from another son.

Thompson: ... we are not going to go through the semantics. Now I saw the cyclone fences that were made as cages. And you did too. All you have to do is admit it. If it's a bad policy, then change it, but don't mislead the committee.

Nielsen: Sir —

Thompson: Do not mislead the committee.