TEHRAN (Reuters) - A suicide bomber has killed six senior Revolutionary Guards commanders and as many as 29 other people in one of the boldest attacks on Iran's most powerful military institution.
The attack, in the country's turbulent southeast, comes as Iranian officials are due to meet their Western counterparts in a sensitive second round of negotiations in Vienna on October 19 intended to resolve a standoff with the West about Iran's nuclear ambitions.
State media said a local rebel group called Jundallah (God's Soldiers) claimed responsibility for the attack, the worst on the elite Revolutionary Guards in recent years, which injured another 28 people at a meeting of tribal chiefs.
"Rigi's terrorist group has claimed responsibility for the attack," it said, referring to Abdolmalek Rigi, leader of Jundallah, which is linked by some analysts to the Taliban in neighboring Pakistan.
But the Guards themselves accused "foreign elements" linked to the United States of involvement. Tehran accuses the United States of backing Jundallah to create instability in the country, a charge that Washington denies.
State television also pointed the finger at Britain, another traditional foe of Iran.
The Revolutionary Guards is an elite force seen as fiercely loyal to Iran's Supreme Leader Ayatollah Ali Khamenei. Its power and resources have increased in recent years. It handles security in sensitive border areas.
The bombing and allegations of foreign involvement risk overshadowing the nuclear talks in Vienna, between Iranian, U.S., French, and Russian officials.
"Attacker detonated explosives strapped to his body during gathering of tribal heads," state-run Press TV said in a headline, adding that civilians and tribal leaders were also among the victims.
State broadcaster IRIB said the attack occurred in the morning at the gates of a conference hall in the city of Sarbaz in Sistan-Baluchistan. The province is the scene of frequent clashes between security forces, Sunni rebels and drug traffickers.
Two high-ranking commanders among the dead were the deputy head of the Guards' ground forces, General Nurali Shushtari, and the Guards' commander in Sistan-Baluchistan Province, General Mohammadzadeh, news agencies reported. Shoushtari was also a senior official of the Guard's elite Quds force.
Citing authorities and experts, a presenter of English-language Press TV said "the finger of accusation is directly pointed at the Jundallah group," referring to ethnic Baluch Sunni insurgents who have been blamed for previous attacks in the region.
The Revolutionary Guards pointed the finger at U.S. involvement. "Surely foreign elements, particularly those linked to the global arrogance, were involved in this attack," a Guards statement quoted by television said. Iran often uses the term "global arrogance" to refer to the United States, its old foe.
State TV also singled out Britain. "Some informed sources said the British government was directly involved in the terrorist attack...by organizing, supplying equipment and employing professional terrorists," it said.
Jundallah, which claimed responsibility for a bomb attack on a Shi'ite mosque in May that killed 25 people, says it is fighting for the rights of the Islamic republic's minority Sunnis.
Some analysts believe that Jundallah has evolved through shifting alliances with various parties, including the Taliban and Pakistan's ISI intelligence service, who saw the group as a tool against Iran.
Predominantly Shi'ite Muslim Iran has also linked Jundallah to the Sunni Islamist Al-Qaeda network. Most people in Sistan-Baluchistan are Sunni Muslims and ethnic Baluchis.
Iran rejects allegations by Western rights groups that it discriminates against ethnic and religious minorities.
The attack is likely to harden the resolve of the clerical and military establishment in confronting the opposition to a disputed election in the summer which saw the reelection of President Mahmud Ahmadinejad.
Iranian opposition leader Mir Hossein Musavi on October 18 said he would press ahead with efforts to reform the Islamic republic despite a crackdown on protests after the June 12 presidential poll, his website said.
The election plunged Iran into its deepest internal crisis since the 1979 Islamic Revolution. The opposition says more than 70 people were killed as Revolutionary Guards and Islamic militia put down the protests that erupted after the poll.