At least 21 people, including members of the elite Revolutionary Guards, were killed and 100 wounded in suicide attack at a Shiite mosque in the southeast Iranian city of Zahedan on Thursday, Iranian media reported.
No group immediately claimed responsibility for the two suicide bombings in front of Zahedan's Grand Mosque, although a lawmaker said he believed the Sunni rebel group Jundollah was behind the attack.
"In the two explosions in Zahedan more than 20 people were killed and over 100 were injured," Fariborz Rashedi, head of the emergency unit at Sistan-Baluchestan province told IRNA.
It later quoted Zahedan prosecutor Mohammad Marzieh as saying that 21 people had died.
Iran's deputy Interior Minister said "a number of Iran's Revolutionary Guards were killed and injured", the semi-official Fars news agency reported.
Zahedan's MP Hoseinali Shahriari told Fars that he believed Sunni rebel group Jundallah was behind the explosions.
Iran hanged Jundallah's leader, Abdolmalek Rigi, last month for his involvement in earlier deadly attacks in Iran.
Predominantly Shiite Muslim Iran arrested Rigi in February, four months after his Jundallah group claimed a bombing which killed dozens of people, including 15 members of the Guards. It was the deadliest attack in Iran since the 1980s.
Zahedan is the capital of Sistan-Baluchestan province which shares a border with Pakistan. The province faces serious security problems and there are frequent clashes between police and drug dealers and bandits.
In May 2009, a suicide bomber killed 30 people and wounded more than 120 in an attack on a mosque in Zahedan.
Jundallah is an insurgent group that says it is fighting for the rights of Iran's Sunni Muslim minority.
Iran grapples with ethnic and religious tension in the southeastern province of Sistan-Baluchestan where authorities have responded to attacks by Sunni rebels with a spate of hangings. Rights groups and the West have condemned the hangings.
Iran says the Sunni group has links to Sunni Islamist al-Qaeda and in the past has accused Pakistan, Britain and the United States of backing Jundallah to create instability in southeast Iran. The three countries have denied this.
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