Immigrant children in California have written heartfelt letters to Pope Francis seeking his help and his prayers for their parents who have been deported or arrested.

"They know that Pope Francis himself is the son of an immigrant. They know that he has the heart to understand what they are going through," Los Angeles Archbishop José H. Gomez said Jan. 14.

The archbishop said that reading the letters "makes my heart ache."

"They are so beautiful and so sad," he told the civic group Town Hall Los Angeles. "My friends, this is what immigration is doing to the soul of our country. How we respond to these children is a challenge to our conscience – and it will be a measure of our humanity."

A letter from Karla, a 15-year-old girl born in Los Angeles, told Pope Francis she has a "very religious" family. Both her parents and her two older siblings are immigrants from Mexico.

"My mom is slowly going blind and my dad has a heart problem. My sister is in a wheelchair and she needs medical help, but they can't get the medical help they need because they don't have their legal documents," she said.

"I know there are more people with the same or even worse situation. Some kids even younger than me have been separated from their parents and family," Karla added. "I ask you to keep me and my family in your prayers."

She also asked the Pope to pray for President Obama "so he can stop all deportation."

The children's letters were collected through a coalition seeking full rights for immigrants. The children brought the letters to the Cathedral of Our Lady of the Angels.

Archbishop Gomez said he was forwarding the letters to the Pope. According to the archbishop, the U.S. government has deported nearly two million immigrants in the last four years.

Another young girl, Guadalupe, asked for the Pope's help "to stop deporting families and separating families because its sad to see kids be separated from their parents and the kids ending up as orphans."

"I hope you can help us with this fight. You are our hope for all the families getting separated," the girl told Pope Francis. She said she knew how it feels to be separated from her father, who died in October 2013.

"It could be the worst feeling you can experience in life. I was not able to see him ever again," she continued.

"The last time I talked to him he said he was coming soon," said Guadalupe, who wrote her letter "with tears in my eyes."

Mario, 14, told Pope Francis he was "a Dreamer – a person who is not born in the United States."

He said his father had provided for his family, but is now in jail. His mother has since been providing for the family through "non-stop hard work."

"I beg you with all my heart to pray for all the people who are going (through) my situation," Mario wrote.

A 17-year-old girl named Leydi asked the Pope to pray for her father "because they are going to deport him."

Leydi, who has three brothers and a sister, said her father left for Tennessee two years ago to work and was now in jail. "He isn't mean, he isn't a bad father, he has always been there for me and my family," she said.

"I miss my father so much," she said, adding that she would like "the most" to have her father at her graduation.

"I would want for you to please help us," she said to Pope Francis. "My family has always been close and the only reason we accepted him leaving was because we need the money in order to survive."

She also characterized herself as a "Dreamer," saying she came to the U.S at the age of four.

"I am doing the best that I can in order to succeed and become a U.S. citizen," Leydi wrote, adding that she is looking for work to help support her family.

Another girl, Jersey, wrote the Pope on her birthday, wishing that her father were with her. "It has been so long that he hasn't been with me on two of my birthdays, last year and today."

She said her father had been working in construction to support the family. "Every single day he used to come home from work exhausted and tired."

Jersey said her father has been detained by immigration police.

"The police will be deporting him and I wonder what will happen and how this will affect my family," she told Pope Francis. "I hope that you can please do something about all families that are going through the same situation."

"Since you are the closest to God I beg you to help my family," the girl said. She also asked for prayers for her grandfather Felix "because he was very sick and today he passed away."

Archbishop Gomez is one of the U.S. bishops' leading advocates of comprehensive immigration reform. He has called on U.S. citizens and leaders to remember "the human faces of immigration reform."

According to the archbishop, there are about 2.6 million undocumented immigrants in California and 11 million in the U.S. as a whole.