At least 21 people, some of them Revolutionary Guards, were killed and 100 more were injured in two suicide bombings in Iran last night.
The bombings were carried out near the Grand Mosque in the city of Zahedan, the capital of the Sistan-Baluchestan province which borders Pakistan.
Jundollah, a rebel Sunni muslim group, claimed responsibility for the slaughter in an email to the Dubai-based Al Arabiya television station.
The group said it had carried out the attack in revenge for the execution by the Iranian authorities in June of its leader Abdolmalek Rigi.
Rigi had been arrested in February and was convicted of carrying out other terrorist attacks. The arrest came four months after the rebel group had admitted it was behind an attack, the deadliest in Iran since 1980, which had left dozens of people dead.
The email sent by Jundollah, which claims to be fighting for the rights of Iran's Sunni Muslim minority, identified the bombers as the former leader's relatives Abdolbaset and Mohammad Rigi.
Fariborz Rashedi, head of the emergency unit at Sistan-Baluchestan province, told the official IRNA news agency, that the bombs had caused carnage: "In the two explosions in Zahedan more than 20 people were killed and over 100 were injured."
Ali Abdollahi, Iran's deputy Interior Minister with responsibility for security, was reported as saying that "a number of Iran's Revolutionary Guards were killed and injured".
Emergency workers were last night faced with the grizzly task of collecting and identifying all the body parts scattered around the mosque by the explosions.
Iran is grappling with ethnic and religious tension in the south-eastern 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.
The authorities have linked Jundollah to the al-Qa'ida network, a charge the rebel group denies, and has accused the US of backing it in order to create instability in the country, a charge Washington denies.
Yadollah Javani, an official with the Revolutionary Guards, persisted last night in blaming Western and Israeli countries for the suicide attacks and claimed they had been implicated by "confessions" given by Abdolmalek Rigi before he was put to death. He said they "prove that America, Israel and some European countries are directly involved in the attacks".