(CNN) -- Iranian authorities have moved imprisoned American Saeed Abedini to a more dangerous prison and are now prohibiting visits from the family of the Christian pastor, according to the public interest law firm representing Abedini's family in the United States.
Abedini, 33, is an Iranian-born U.S. citizen who makes his home in Boise, Idaho, with his wife and two small children.
He converted to Christianity from Islam. In the Islamic Republic of Iran, a Muslim who converts to another faith can face the death penalty. Abedini was arrested in June 2012 during a visit to his native country.
In a news release, the American Center for Law and Justice (ACLJ) said that one of Abedini's Iranian family members went to visit him at Evin Prison in Tehran on Sunday and was told that Abedini had been moved the previous day to Rajai Shahr Prison near Karaj. The family member then made the hour-and-a-half drive to Karaj and was told that Abedini was not permitted to receive visitors.
The ACLJ pointed out that the transfer occurred at the same time demonstrators in Iran were chanting, "Death to America!" in rallies observing the anniversary of Iranian protestors seizing the U.S. Embassy in Tehran in 1979.
U.S. Secretary of State John Kerry says Iran has detained Abedini since Sept. 26, 2012, sentencing him to eight years in prison, "on charges related to his religious belief." Kerry has called for Iran to release him.
Appearing on CNN's "The Lead with Jake Tapper," on September 24, near the one year anniversary of his imprisonment, Abedini's wife, Naghmeah, said, "His charge was undermining the Iranian government, the basis for the charge was Christian gatherings."
She said that at the time of Abedini's arrest, he was in Iran with that government's permission to build a nonsectarian orphanage on his parent's property. She said that he had worked with house churches on visits prior to the one during which he was arrested.
U.S. President Barack Obama also has called for Abedini's release.
On September 27, Obama spoke by phone with Iranian President Hassan Rouhani when Rouhani was in the United States for a speech at the United Nations. The call was the first time presidents from the two nations have spoken directly since the U.S. severed diplomatic ties with Iran following the Islamic Revolution and the seizing of hostages at the U.S. Embassy in Tehran.
A senior official in the administration told CNN that the president "noted our concern about three American citizens who have been held within Iran -- Robert Levinson, Saeed Abedini, and Amir Hekmati -- and noted our interest in seeing those Americans reunited with their families." Levinson, a retired FBI agent, vanished during a business trip to Iran in March 2007. Amir Hekmati is a former U.S. Marine who was jailed in Iran in 2011, with the Iranian government accusing him of espionage
Faraz Sanei, Iran researcher with Human Rights Watch, said that "prisoners of conscience" incarcerated at Rajai Shahr Prison are comingled with violent offenders, such as those serving time for murder convictions. He also cited reports of overcrowding, lack of running water, lack of heat in the winter, and negligence on the part of jailers.
He said prisoners regularly do not receive needed medical care, and some have staged hunger strikes in an effort to receive more humane treatment.
Regarding Saeed's case Sanei said, "Saeed Abedini is among the dozens of Iranian Christians who have been subjected to surveillance, harassment, arbitrary arrests and detentions, and unlawful convictions during the past few years because of the Iranian government's crackdown on Christian converts and the home church movement.
"Iran's judiciary should immediately free Abedini and others like him, and allow Iran's Christian community, and particularly members of the country's besieged home church movement, to practice their faith free from government interference."