Iran may have taken the 9^th spot in the 2016 Watch List of most severe persecutors of Christians but this has not deterred thousands to become Christians and join underground house churches, despite being illegal in the country.

According to Open Doors spokeswoman Emily Fuentes, the number of people who have joined these house churches has reached close to one million people, but based on its trajectory, it would be safe to say that Iran has the fastest growing evangelical population in the world, reported Catholic Online. 

"The house churches are causing such rapid growth in conversions it is unmatched by any other country in the Middle East," she said.

The Islamic Republic of Iran is based on a Shi'a Muslim theocracy, meaning that Iran's Christian house churches are considered illegal while those who join them are faced with the threat of imprisonment.

According to the U.S. Commission on International Religious Freedom (USCIRF), Iran's government uses these religious laws as a means to prevent people from exercising their internationally protected rights to freedom of expression of religion or belief.

However, these strict religious laws may also be the reason behind the drastic increase in the number of converts who have chosen to embrace Christianity at the risk of being arrested for their faith.

Fuentes said that the severity of persecution and dissatisfaction with the Islamic regime have prompted people to seek Christianity.

"I have talked to an Iranian Christian who called Ayatollah Khomeini, the founder of the Islamic Republic, the greatest Christian missionary in the history of Iran because he established the Islamic Republic which is now pushing people to Christ," said Todd Nettleton of Voice of the Martyrs.

As part of the underground church, Iran Alive Ministries has used broadcasts to spread the gospel to tens of thousands of Iranians, reported Christian Headlines.

"[I]nto that void in the hearts of Iranians, the gospel message of a Savior who loves them enough to die for them is like sweet music. And it is coming on radio waves, over satellite television, online, and even in supernatural means like dreams and visions," he said.