Among those killed were a members of the elite Revolutionary Guards.
The Sunni Muslim rebel group Jundollah said it was behind the attacks, telling Al Arabiya TV in an e-mail that it had carried them out in retaliation for Iran's execution in June of the group's leader, Abdolmalek Rigi. Rigi was hanged after being convicted of carrying out other deadly attacks. His younger brother Abdolhamid was hanged one month earlier in Zahedan. The suicide bombings took place near Zahedan's Grand Mosque, and Jundollah said they were carried out by relatives of Rigi and were aimed at a Revolutionary Guards gathering. The group said the suicide attacks were carried out by Abdolbaset Rigi and Mohammad Rigi. It warned of more operations to come.
Zahedan is the capital of Sistan-Baluchestan province which shares a border with Pakistan. The province is known for its instability and faces frequent clashes between police and drug dealers, smugglers and bandits.
Iran accuses Jundollah of having links to al-Qaeda and has also accused Pakistan, Britain and the United States of backing Jundollah to create instability in southeast Iran. All three countries have denied this, and Jundollah denies having any links with al-Qaeda and says it fights for more rights for the Sunnis in Baluchestan.