MINNEAPOLIS - Shane Bauer wove an engagement ring out of threads from his shirt, then met his girlfriend, Sarah Shourd, in an unlikely place for a marriage proposal: the exercise yard of the Iranian prison where the couple have been locked up for nearly a year.

The mothers of both Americans said Monday that their children would get married whenever they are released. They, along with Josh Fattal, were taken into custody and accused of spying for the United States when they went for a hike in July along the border between Iraq and Iran.

The engagement "shows they're continuing to have hope. They're planning for the future, which is very good," said Bauer's mother, Cindy Hickey of Pine City, Minn. Her comments came two days after she, Nora Shourd of Oakland, Calif., and Laura Fattal of Elkins Park returned to this country after a short visit to see their children.

Hickey said her son had fashioned the crude engagement ring and proposed in January at Tehran's Evin Prison. Bauer, 27, and Shourd, 31, have been a couple for more than three years, Hickey said, and had been discussing marriage before their capture.

Bauer and Fattal, 27, share a prison cell. Shourd is held separately but is allowed to see the two men for about an hour each day. On the day Bauer proposed, he asked Fattal to hang back from their daily meeting so he could pop the question, the mothers said. Fattal will be the couple's best man.

The engagement offered a glimmer of good news to the hikers' families after a disappointing visit in which the mothers had hoped to bring their children home.

Over the weekend, Iran's intelligence minister said his country would be open to a prisoner swap if Washington made a humanitarian gesture toward Iranians in U.S. custody comparable to the decision to permit the mothers' visit.

"We've heard that before, and the thing is we have no control over it," Hickey said of a potential prisoner swap. "We can't spend a whole lot of time thinking in that direction."

The mothers said they were happy to see their children keeping busy, mostly through reading, studying, and exercising. Still, Shourd's mother said, all three show the burden of months behind bars. "There's a heaviness, an anxiety to them," said Nora Shourd. "I think it's never far from their minds: 'Just what in the world are we still doing here?' "

Laura Fattal said she was still hopeful her son would be home for his 28th birthday June 4. "We keep hoping, and we are continually optimistic," she said. "I don't even like to think that 10 days from now they will still be in captivity."