Immigrant mothers held at a Berks County, Pa., detention center, some for as long as a year, began a hunger strike Monday to draw attention to what they describe as a "desperate situation" for themselves and their children.

The 22 women, most from Central America, say they fled violence in their homelands and are seeking asylum in the United States. They have been locked up pending the outcome of court cases to deport them.

Erika Almiron, director of the Philadelphia-based immigrant support group Juntos, said Homeland Security Secretary Jeh Johnson told a news conference last Friday that the average stay was 20 days or less. The mothers dispute that.

A total of 32 women are housed at the Berks center. They say they and their children, ages 2 to 16, have been detained for 60 to 365 days.

"On many occasions our children have thought about suicide because of the confinement," they wrote. "They ask us if we have the courage to escape. . . . We are desperate, and have decided that we will get out alive or dead."

Calling themselves "Madres Berks," they did not sign the letter but identified themselves by their children's ages and the number of days they have been incarcerated.

Advocates for the women say some staff at the center threatened the hunger strikers, saying if they did not resume eating they could grow so weak that their children would have to be taken from them.

A spokesman for U.S. Immigration and Customs Enforcement said the 75 residents at the facility have access to meals served three times a day in the cafeteria and free snacks.

According to ICE protocol, hunger strikers are to be referred for medical supervision and evaluation only after not eating for more than 72 hours or missing nine meals.

For that reason, said the ICE official, "currently no residents at the facility are considered to be on hunger strike."