An Iranian pastor who was put on death row for apostasy in 2010 and then acquitted about two years later, was rearrested along with his wife and another church member on May 13, according to Christian Solidarity Worldwide.

Youcef Nadarkhani was arrested in 2009 when he questioned the influence of the Islamic teachings in his child's school, which he believed was unconstitutional. He was also trying to register his church at the time. A year later, he was charged with apostasy and sentenced to death by hanging. During the court proceedings, he was repeatedly asked to renounce his faith, but he refused.

In September 2012, he was released from prison amid international pressure and acquitted of apostasy charges, but received three years of imprisonment for evangelizing to Muslims.

On Christmas Day, about three months later, he was re-arrested to complete his three-year sentence. He was again released in January of 2013.

After the pastor was released, his legal counsel and prominent human rights lawyer Mohammed Ali Dadkhah was put into prison for 10 years, and banned from law practice for keeping prohibited books at home and for "actions and propaganda against the Islamic regime." Dadkhah was also released, upon condition of adherence to strict state guidelines.

"Unfortunately, it is not uncommon for Christians who have been arrested on account of their religious beliefs to be released and re-arrested time and again, in a tactic designed to foster a sense of insecurity within the community," said CSW's Chief Executive Mervyn Thomas.

The Iranian authorities did not specify the charges against him, nor how long Pastor Nadarkhani will be in prison.

"We urge the authorities ensure Pastor Nadarkhani, Tina Nadarkhani and Yasser Mosayebzadeh receive due process, and once again call on Iran to fully respect its constitutional and international human rights obligations by ensuring that justice and equality before the law are guaranteed to all citizens, regardless of their religion or belief," Thomas added.

When Pastor Nadarkhani was set free in September 2012, he wrote an open letter of "gratitude" to the international community who worked for his release after being jailed for "the cause" he defended, which was to stand for Christ.

"Indeed I have been put to the test, the test of faith which is, according to the Scriptures 'more precious than perishable gold.' But I have never felt loneliness, I was all the time aware of the fact that it wasn't a solitary battle, for I have felt all the energy and support of those who obeyed their conscience and fought for the promotion of the justice and the rights of all human beings," he said.

A 2015 study by Christians in Parliament reported that arbitrary detention of believers continue unabated even after pre-election promises of president Hassan Rouhani to protect religious freedom of minorities. A simple prayer or Bible study gathering is regarded as a political maneuver against national security of Iran, for which Christians are put into prison where they face "severe physical and psychological torture."

Another Iraninan Pastor Behnam Irani, who has been serving a six-year sentence in jail since 2011 for crimes against "national security," is seriously ill and is suffering from an unknown sickness.

Pastor Saeed Abedini, an Iranian American Christian, was detained in 2012 and sentenced to eight years in prison on charges of undermining national security, but was released earlier this year after years of intense international lobbying on his behalf.