Washington (CNN) Rep. Beto O'Rourke charged Thursday that racism is a factor in Trump administration policy leading to the detention of children at the border.

"This is a President who has called those asylum seekers, some of those asylum seekers, animals," the Texas Democrat said. "He's talked about this as an infestation. He's described immigrants from Mexico as rapists and criminals. ... There is a strong racist element to this policy."

O'Rourke, in an interview on CNN's "The Situation Room with Wolf Blitzer," said he was concerned about the lack of information the administration had provided on children it is separating from parents who have crossed the border illegally.

He described a visit to a border patrol station in McAllen, Texas, last week and said that when he asked a border official if they could track children after they went into the custody of the Office of Refugee Resettlement, the official said, "We don't know."

"They are not answering any of our questions," O'Rourke said of the federal government. "We are asking, for example, where are the girls? When I go to these detention centers and these processing centers, I see a lot of young boys. I don't see the girls. They won't tell us where they are."

Read More