The wife of a prominent Christian pastor imprisoned in Iran has described how her family has been "torn apart" by their ordeal. But they have kept their faith, she explained, adding: "Jesus hasn't abandoned us."

Saeed Abedini, a convert to Christianity from Islam, was sentenced to eight years in prison in 2013 for having created a network of Christian house churches and for allegedly "attempting to sway Iranian youth away from Islam".

His wife Naghmeh told a US Congress hearing of the foreign affairs committee that since her husband was detained in 2012, she has needed to leave their two children, both still at elementary or junior school, at home while she has travelled the world campaigning for her husband's release. She said she could not bear the "crushed hopes" of her children any more.

In her testimony she added: "Most mornings like today, I wake up in a new hotel in a new city or country and am reminded of my new reality — a reality that includes lonely airports and empty hotel rooms. This pain of this journey without my husband has only increased as I have had to frequently leave my children to advocate for my husband's release. The reality is, we are a family torn apart.

"Over the last three years, I have had to watch my two children, Rebekka (who is 8 years old) and Jacob (who is 7 years old), suffer daily as they have grown up without a father or a mother," Abedini continued. "I am here today as single mother who is trying to be strong for her children, and as a wife who humbly admits, I need your help. I cannot bear to look at my children's longing eyes one more time and explain to them why their daddy is still not home."

She said no religion in the world could ease the pain, although there was some comfort in an intimate relationship with Christ.

"When you are living a nightmare no religion in the world can help you. The do's and dont's of religion cannot bring much peace and comfort. Only an intimate relationship with our Maker can bring about the supernatural peace and strength that is covering our family today. And that relationship is only possible through the acceptance of the heavy price of sin that was paid on the cross by Jesus Christ. Today that salvation is available for all who believe."

Her husband had been protected by this, she said.

"Saeed is so strong in his faith because even though we are not there and even though the Church is not there, he's got Christ there with him, strengthening him. Other prisoners have said that usually when prisoners come out of solitary, they are devastated or broken, but he seemed so refreshed and glowing. That's what we have in that relationship with Christ."

She referred to the biblical story told in Daniel 3, when three men were thrown into a roaring furnace by King Nebuchadnezzar because they refused to deny their faith and worship his gods instead. They emerged, unharmed by the flames, and a fourth man was seen walking with them.

Mrs Abedini said: "During the last three years Jesus has never abandoned Saeed and me. He has been with us during the fiery furnace even when the furnace had been heated seven times hotter than usual. He has dried every tear and has given us the strength to endure."

Although he has not broken any law, Iranian officials have made clear to Abedini that he will not be released unless he abandons what is seen in Islam as apostasy, and re-embraces the religion he was born into.

After the hearing, Mrs Abedini told the Christian Post: "The times they have moved him in and out of solitary and the times they have threatened him, they said 'You will stay here longer than the eight years and your only key to freedom is if you deny your Christian faith and you return to Islam.' The guards have said that, officials have said that continuously.

"When family has followed up with the Supreme Leader's office or the judiciary, they have continuously said his only key to freedom is if he recants his Christian faith and returns to Islam."

Family members of three other Americans imprisoned in Iran also testified at the hearing.

There is growing pressure on the United States government to cease negotiations on a nuclear deal with Iran until all four Americans have been released.