The Associated Press
By NASSER KARIMI
The attacks took place in Zahedan, the capital of a lawless province near Pakistan and Afghanistan that has witnessed attacks by Jundallah, a militant group that claims to be fighting for the rights of minority Sunnis and is believed to have al-Qaida links.
Abdel Raouf Rigi, a Jundallah spokesman, told Al-Arabiya television that his group was responsible for Thursday's attack and said it was carried out by a suicide bomber targeting a secret meeting of Iran's elite Revolutionary Guards that was taking place inside the mosque.
Iran's supreme leader, Ayatollah Ali Khamenei, blamed "interventionist powers" of trying to incite sectarian conflict with the mosque bombing, and the country's interior minister specifically accused the U.S. and Israel.
Iran often blames Western powers for violence inside the country — accusations they routinely refuse as the U.S. did Friday.
"We condemn this terrorist attack in the strongest possible terms and extend our sympathy to the families of those injured and killed," State Department spokesman Ian Kelly told reporters in Washington.
"We do not sponsor any form of terrorism in Iran and we continue to work with the international community to prevent any attacks against any innocent civilians anywhere," he said.
It was unclear if there was any connection between the two attacks in Zahedan, located some 1,000 miles (1,600 kilometers) southeast of Tehran.
The three gunmen who attacked the campaign office insulted and threatened people before opening fire and injuring two office workers and an infant, the Islamic Republic News Agency quoted the office chief, Mohammad Zahed Sheikhi, as saying. The men were captured after a short chase, he said without providing further detail.
The attack comes two weeks before Ahmadinejad faces a tough election against three other candidates, two of whom are reformists who have criticized the president's performance and hope to improve relations with the West.
Ahmadinejad and other hard-liners in the government have often had a hostile relationship with the U.S. and its allies, reflected in the frequent accusations that the countries are fomenting unrest in Iran.
"I announce that … those who committed the bombing are neither Shiite nor Sunni. They are Americans and Israelis" who want to stoke sectarian conflict in the country, Iranian Interior Minister Sadeq Mahsouli said on the ministry's Web site.
Khamenei urged Sunni and Shiite leaders in a message read by state television temper their reaction to the attack and distance themselves from extremists.
The Martyr Foundation, a government organization that provides financial support to victims of terrorist attacks in Iran, said 25 people were killed in the bombing in Zahedan's second-largest Shiite mosque.
Jalal Sayyah, a senior security official in Zahedan, said 145 people were injured in the bombing and three suspects have been detained.
"Hire of the terrorists by the U.S. was verified based on investigation," Sayyah told The Associated Press.
Sayyah did not say whether the terrorists belonged to a specific group. In 2007, Jundallah, or God's Brigade, killed 11 members of Iran's elite Revolutionary Guards in Zahedan.
Iran blamed a similar bombing of a Shiite mosque in the country's southwest in April 2008 on three men it said had ties to the U.S. The bombing in the city of Shiraz, located some 550 miles (885 kilometers) south of Tehran, killed 14 people.
Last month, Iran hanged the men, who the court said were members of a little known monarchist group that wants to overthrow the country's ruling Islamic establishment.
