Three more members of the Jundallah militant group were arrested, the IRINN Iran TV channel's website quotes the Iranian Sistan-Baluchistan Province's Security Department chief director Alirza Panahian as reporting.
According to him Jundallah's arrested members are charged with Zahedan mosque bombing.
On the night of July 16, two bombs were detonated in quick succession in front of the Zahedan Grand Mosque in Sistan-Baluchestan Province. At least 27 people lost their lives and more than 270 others were injured in the incident.
The terrorist group Jundallah claimed responsibility for the attacks.
According to official data, 21 and then four more people were arrested in connection with the incident.
The pervious major blast committed by the "Jundullah" group took place in October 2009, which caused 50 peoples' death.
The Zahedan city is an administrative center of the Sistan-Baluchistan Province and is located on the border with Pakistan.