Three imprisoned Christians in Iran are effectively being kept in jail as their bail is set unusually high, according to Christian Solidarity Worldwide (CSW).

Yasser Mossayebzadeh, Saheb Fadai and Mohammadreza Omidi (Youhan) were arrested on May 13 in Rasht, Iran as part of a series of raids targetting Christian homes. A Christian pastor and his wife were also arrested, but were released on the same day, according to CSW.

The three men from the Church of Iran are being held in prison pending payment of 100,000,000 Toman each (approximately US$33,000).

"Unfortunately the authorities appear to be resorting once again to a tried and tested policy of demanding excessive bail designed primarily to cripple members of the Christian community economically and to delay the release of detainees. By setting such exorbitant bail amounts without proffering substantiating charges the Iranian authorities merely seek to punish these men," said Mervyn Thomas, chief executive of CSW.

When the homes of Fadai and Omidi were raided their Bibles, computers and mobile phones were reportedly confiscated.

CSW say 10 Christian homes were raided on the same day.

Each of the men have been previously detained by Iranian authorities. Omidi was one of four Christians sentenced to 80 lashes in 2013 for drinking alcohol during a communion service and possessing a receiver and satellite antenna.

The three men are still in Lakan Prison near Rasht, pending payment of bail.

The reasons behind their arrest are yet unclear as charges have not been made.

"With Iran re-entering the international fold we were hoping for improvements in human rights situation, but it is now clear that no improvement has taken place," Firouz Khanjani, a member of the National Council fo the Church of Iran told CSW.

"CSW deplores the return of exorbitant bail demands for the temporary release of detainees who have committed no crime and urges the Iranian authorities to cease this practice. We also call for the immediate release of Mr Mossayebzadeh, Mr Fadaie and Mr Omidi, who continue to be held without charge, and for Iran to ensure that justice and equality before the law are guaranteed to all citizens, regardless of their religion or belief," said Thomas.