NEW YORK -- Pope Francis, speaking Monday from Rome via satellite to people in three American cities, asked a teenage girl to sing for him as he sought prayers for his upcoming trip to the United States.

The pope spoke with people in Los Angeles, Chicago and McAllen, Texas, in an event arranged by ABC News.

The 17-year-old girl in Chicago, Valerie Herrera, wept as she told Francis she'd been bullied because of a rare skin condition and had turned to music for comfort. He said in English, "I would like to hear your singing. May I ask of you to sing a song for me?"

When Valerie hesitated, he said, "Be courageous."

She then sang in Spanish, and he smiled and thanked her.

Francis will make his first visit to the United States starting Sept. 22 in Washington, then moving to New York and Philadelphia.

"I'm praying for all of you, the people of the United States, and I ask you to pray for me," Francis said.