McAllen, Texas (CNN) Chanting protesters briefly blocked a bus leaving a migrant detention center in McAllen, Texas, on Saturday afternoon.

Protesters stood in front of the bus and yelled, "Set the children free" and "Shame on you" at Border Patrol officers. The Border Patrol ended up surrounding the bus so it could back up and go out the other end of the street.

CNN reporters could see children through the darkened windows, and a protester told CNN she also saw children through the windows. She said some of the children waved at her and she told them, "You are not alone" in Spanish.

A bus leaving a detention center in McAllen, Texas, was blocked by protesters Saturday.

"It was very difficult to see," said Denise Benavides of Dallas, who said she's a member of the League of United Latin American Citizens

Benavides said she didn't know where the bus was going but "that's something we'll look into -- what's going on and where are they taking these children."

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