They are held alone in separate rooms and only occasionally allowed outside. In 12 weeks they have had one visitor. They pass the time with exercises, meditating and frequent weeping. According to their families, they are “very, very scared”.

Solitary confinement is hard enough at the best of times but the plight of Laura Ling and Euna Lee, two journalists from San Francisco, is especially grim. Not only are they being held in North Korea, one of the world’s most terrifying dictatorships, they are caught up in a game of power politics involving intercontinental rockets, nuclear weapons and the UN Security Council.

On Thursday the two women will go on trial in North Korea’s highest court for allegedly entering the country illegally while researching a television news story about North Korean refugees in China. Their prospects of a fair trial were already vanishingly slight, but they have dwindled still further as North Korea has carried out a series of defiant gestures which have brought the region close to crisis.

Having remained silent in the hope that the situation would resolve itself, the families of Ms Ling and Ms Lee have now spoken out about their situation as rallies in their support are planned across the US. “We have been holding our breath as we’ve watched the political situation grow increasingly tense,” they said, a week after North Korea undertook its second underground nuclear test. “As their days in detention progress, we have become increasingly concerned about their well-being and state of mind. ThoughThe girls are strong, We know that they are very, very scared.”

Part of a letter released by her family makes clear the mental strain being experienced by 32-year-old Ms Ling.

“When I first got here, I cried so much. Now, I cry less. I try very hard to think about positive things, but sometimes it is hard to. Some days I get to go outside and get some fresh air. In the early evening, I do some stretching ... I breathe deeply and think about positive things that have happened in the day. For example, I think ’I’m lucky I made it through another day.”

The two women, employees of Current TV, a San Francisco-based company founded by the former vice-president Al Gore, travelled to China’s long and porous border with North Korea on 12 March, and somehow found themselves on the wrong side of it.

Conflicting and unsubstantiated reports suggest that they either took the risky step of crossing the frozen river which marks the frontier, or were lured or abducted to the other side.

If convicted of so far unspecified “hostile acts”, they could in theory be sent to a labour camp for as long as ten years.

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