MINNEAPOLIS -- Two Americans held in Iran on espionage charges told their families during brief phone calls over the weekend that they haven't had access to their lawyer and do not know what is happening in their cases, their families said Monday.

Both calls came early Saturday and lasted about five minutes each. Shane Bauer called the cell phone of his mother, Cindy Hickey of Minnesota, at about 6 a.m. Central time. Josh Fattal called his parents' suburban Philadelphia home about an hour later.

Hickey said her son sounded "strong but frustrated." Fattal's mother, Laura Fattal, said it was "joyous" to hear her son's voice but that it also underlined her family's heartbreak at his continued imprisonment. Both mothers said the men have few details of Iran's case against them and haven't been allowed to speak to their Tehran-based attorney for several months.

"He said, 'I have no idea what's going on with my case, what's happening with it,"' Hickey said. "I just told him that we're working on this, to have faith that we're going to do everything we can to get him home."

Iran has accused Bauer, Fattal and Bauer's fiance Sarah Shourd of espionage after they were arrested near the country's border with Iraq in July 2009 during what their families say was an innocent hiking trip. Iran released Shourd on medical grounds this past September, and a trial in Iran is scheduled for Feb. 6.

Shourd, who lives in the San Francisco area, had arrived at the Fattal home on Friday for a short visit, and was able to speak briefly to Fattal during his call.

Hickey and Laura Fattal said they believe, based on the calls, that their sons have become even more isolated since Shourd was released. They reported getting less time in the prison's exercise yard, and that they had been getting few of the daily letters from family members after previously receiving most of them. Bauer and Fattal also stopped getting books mailed by their families, the mothers said.

"The books and letters are important," Laura Fattal said. "This is their lifeline -- they exercise and they read."

The families had no direct prior warning about the phone calls, but were on what Laura Fattal called "high alert" after officials with the Iranian mission to the United Nations indicated earlier this month that phone calls might be pending. Hickey said she kept her cell phone with her at all times as well as a notebook of things she wanted to talk about. Laura Fattal said her family made sure there was always someone around to answer the home phone when it rang.

It was only the second time Bauer and Fattal called home, the first being last March. The last direct contact family members had with Bauer and Fattal was in May, when Hickey, Laura Fattal and Shourd's mother were allowed to visit their children in Iran.

Both mothers said they continue to hope that Iran will release both men on humanitarian grounds prior to the scheduled trial.