Iranian security forces have detained 20 suspects in connection with a bloody terrorist attack in Iran's eastern Sistan-Baluchestan Province, a senior Iranian judicial official says.

“The public and revolutionary prosecutor's office of Zahedan demanded the execution of four of the perpetrators behind the Chabahar terrorist attack,” IRIB quoted Mohammad Marzieh, the prosecutor of Zahedan, as saying late on Saturday.

In December 2010, a terrorist attack took place at the Imam Hussein Mosque in Chabahar, where people were commemorating the martyrdom of the third Shia Imam, Imam Hussein (PBUH).

At least 38 mourners were killed and more than 89 others, including women and children, left injured. The terrorist group Jundallah has claimed responsibility for the deadly attack.

Marzieh went on to say that the suspects have been arrested on charges of “cooperation with main perpetrators of the attack in transferring explosive belts” and “providing a safe haven for the attackers.”

He further noted that 12 of the detainees are still under investigation and their case would be sent to court for trial.

The Iranian official also added that “Interpol is looking for” those agents who have fled the country after the attack.

The Pakistan-based terrorist group Jundallah has carried out numerous bombings, assassination attempts, and terrorist attacks in Iran.

Its leader Abdolmalek Rigi was arrested by Iranian intelligence forces in February 2010 and executed in June for 79 counts of crime, including armed robbery, bombing operations and armed attacks on police and civilians.

Rigi stated in his confessions that he had dealings with the US government and was promised unlimited funds and resources for “waging an insurgency” in Iran.

Iran says the perpetrators behind the Chabahar terrorist attack were trained and equipped by foreign elements beyond the country's eastern borders in Pakistan.

The Islamic Republic has called on Pakistan's government to step up efforts to secure its borders and prevent terrorists from crossing over into Iran.