President Ahmadinejad is seeking a second term in office
Gunmen have attacked Iranian President Mahmoud Ahmadinejad's election campaign office in Zahedan, a day after a bomb attack in the city, reports say.
A child and two other people were injured when three men opened fire on the office, which covers the south-east of Iran, state media say.
On Thursday, at least 19 people died in a bomb blast in a Shia mosque in the city, which is predominantly Sunni.
A Sunni militant group has reportedly said it was behind the attack.
Abdel Raouf Rigi, described as a spokesman for the Jundallah group, told Saudi-owned TV channel Al-Arabiya that a suicide bomber had targeted a secret meeting of Iran's elite Revolutionary Guards inside the Amir al-Mohini mosque.
Officials have accused the US of being behind the bombing but a US state department spokesman on Friday denied any Washington involvement.
"We condemn this terrorist attack in the strongest possible terms," said Ian Kelly. "We do not sponsor any form of terrorism in Iran."
'Knives and guns'
The gunmen attacked Mr Ahmadinejad's campaign HQ at about 1900 local time (1430 GMT) on Friday, the state news agency Irna reports.
"Three knife-wielding people on motorbikes stopped outside the centre on Saadi Street, cursed, made threats and tore up billboards," Mohammad Reza Zahed Sheikhi, who heads Mr Ahmadinejad's election office in Zahedan, told the news agency.
When campaign workers tried to protest, he added, "the attackers pulled out guns and shot at them".
Police reportedly arrested the assailants as they tried to escape.
The attacks comes at a time of heightened political sensitivity across Iran, with just over two weeks before the
first round of the presidential election.
Zahedan is the capital of a remote province which is one of the most deprived in the predominantly Shia country.
Militants operate in the area, many of them with links to the drugs gangs, and clashes with the security forces are common.
Three people were arrested following the attack on the mosque, according to Jalal Sayah, deputy governor of Sistan-Baluchestan province.