Imprisoned pastor Saeed Abedini was reportedly tortured and interrogated in Iran's notorious Rajai Shahr prison this week, where he is being held on charges of undermining national security.

According to the American Center for Law and Justice (ACLJ) which is supporting Iranian-born Abedini, the pastor told members of his family yesterday that he had been abused both physically and verbally during interrogation. He said a taser gun was used on his head, and he was threatened with new criminal charges.

Iranian intelligence officers have now apparently claimed that Abedini is connected to anti-government groups and has taken action against the Iranian government. The pastor denies the allegations.

Abedini began developing home church communities for Christian converts, who are forbidden from gathering in Iran's public churches, more than a decade ago. He was first arrested in 2009, but was later released after pledging to stop formally organising house churches in the Musilm-led country.

He was arrested for a second time upon returning to Iran in 2012 to help build a state-run, secular orphanage and was held without charges until January 2013, when he received his eight-year sentence. There are now concerns that this sentence will be extended.

Abedini's wife, Naghmeh, has campaigned extensively for her husband's release, and had a private meeting with President Barack Obama in January. Following the latest news of her husband's ill treatment, she said, "When will this nightmare end? Saeed is not a criminal. Being a Christian and motivated by Christian values to help the poorest and most needy children in Iran should be seen as good for the Iranian society.

"Hearing that yet again the hardliners in Iran are trying to fabricate evidence against my husband and that he was abused and tasered is almost too much to bear."

Iranian President Hassan Rouhani is due to speak at the UN General Assembly in New York on September 28, and Naghmeh has urged the international community to use this as an opportunity to call for Saeed's release.

"It is time for governments all over the world to shift their focus to the injustices of the Iranian Government and call on the Government of Iran to free my husband. It is time for businesses seeking to do business in Iran to look beyond their bottom dollar and see the instability of a government known to imprison innocent men and women who have exercised their fundamental freedoms," she said.

"Whether we operate in the field of business, government, or simply are members of human society, we must expect and demand more of our leaders.

"I pray that as President Rouhani plans his travel to the United States next week, he will hear relentless voices crying out for Saeed's freedom."

On Tuesday, the US Commission on International Religion Freedom (USCIRF) marked the three year anniversary of Abedini's imprisonment. It released a statement branding his treatment unjust, and condemning the "harsh and unsanitary conditions" of Rajai Shahr.

"The Iranian government's continued imprisonment of Pastor Abedini is a gross violation of the internationally-protected right to freedom of religion or belief. The Iranian government actively suppresses any religious belief and activity it disapproves of and denies any semblance of rule of law that meets international standards," said USCIRF Chairman Robert P George.

"USCIRF calls on the Iranian government to ensure Pastor Abedini's safety and immediately and unconditionally release him. USCIRF also calls on the United States and the international community to raise Pastor Abedini's case in all international fora, and for the US government to freeze the assets and entry into the US of all Iranian officials responsible for serious violations of religious freedom and related human rights against Pastor Abedini and other prisoners of conscience."

The USCIRF has designated Iran a "country of particular concern" since 1999.