TEHRAN — Preelection tensions rose Friday in Iran's religiously and ethnically mixed southeast after gunmen opened fire on the president's campaign office and a radical group claimed responsibility for the bombing of a mosque the day before that killed up to 23 people and injured scores.
Iranian authorities blamed the United States for the violence in Zahedan, on the border with Pakistan.
"The hands of America and Israel were undoubtedly involved in this incident," prayer leader Ayatollah Ahmad Khatami told supporters in Tehran, referring to Thursday's bombing of a Shiite mosque. "Although Wahhabis and the infidel and evil Salafis were an accomplice to the crime, they were being led from somewhere else."
Wahhabi and Salafi are puritanical schools of Sunni Islam rooted in Saudi Arabia. They have inspired Osama bin Laden and his Al Qaeda terrorist network, as well as the Taliban and other groups that denounce Shiite Islam, the majority sect in Iran.
Khatami is a staunch hard-liner unrelated to former President Mohammad Khatami, who is a moderate.
Iranian allegations of U.S. support for militant groups fighting the government could undermine the Obama administration's attempts to reach out to the Islamic Republic to resolve long-standing disputes, including disagreement over Iran's nuclear program and Tehran's support for militant groups fighting Israel.
The gunmen who opened fire on the campaign headquarters of President Mahmoud Ahmadinejad in Zahedan, capital of Sistan-Baluchistan province, stormed in and ripped up campaign literature, and injured as many as three people, Iranian news agencies reported.
Hours earlier, the Sunni militant group Jundallah, which is linked to Al Qaeda and draws support from Iran's ethnic Baluch minority, claimed responsibility for the mosque bombing on a Shiite holiday. It made the claim in a phone call to the United Arab Emirates-based Al Arabiya satellite news channel.
The caller claimed that the victims were hard-line pro-government militiamen discussing the June 12 election.
Authorities announced the arrest of three suspects, who allegedly crossed into Iran over the barren desert border from Afghanistan or Pakistan with the aim of sowing political and sectarian discord before the vote. The border area has long been the scene of drug trafficking and tribal banditry.
"Evidence shows that these people had direct involvement in the terrorist operation and were linked to enemies outside the borders of the country," said Jalal Sayyah, deputy governor-general of Sistan-Baluchistan, according to a report by the semiofficial Fars News Agency. "This group aimed to create religious disputes, intimidate people and undermine elections in the country by their futile action."
Iranian authorities frequently allege that the U.S. backs Jundallah, but offered no evidence Friday of American involvement.
Members of Iran's Baluch minority, an ethnic group that straddles southeastern Iran, southern Pakistan and Afghanistan, have for years waged an insurgency against the government, striking targets in and around Zahedan. The Taliban has also infiltrated Baluch regions of Pakistan, especially the main city of Quetta.
The U.S. and North Atlantic Treaty Organization are fighting a worsening Taliban insurgency in Afghanistan. Pakistan has launched an offensive against Pakistani Taliban militants about 100 miles from the capital, Islamabad. The bombing in Zahedan was among the clearest signs yet that the troubles afflicting neighboring countries are spilling into Iran.
The attack coincided with major bombings in Pakistan in the last two days that killed dozens of people and came days after Iran held a high-level summit to discuss drug trafficking and terrorism with Afghan and Pakistani leaders.
Mostaghim is a special correspondent.