Iranian state media reported Saturday that at least 25 people were killed and 60 were wounded in an attack on a military parade in the Arab Ahvaz region of the country. President Hassan Rouhani called on the country's security forces to determine who was behind the attack amid competing claims of responsibility.
Heavily armed gunmen rained automatic weapons fire for over 10 minutes on participants of the parade in Khuzestan province. Most of the victims reportedly belonged to Iran's elite Revolutionary Guard.
Iranian TV showed ambulances ferrying dozens of victims to nearby hospitals while survivors could be seen helping those who were injured.
The Iranian Revolutionary Guard commander in charge of Khuzestan province, Hassan Shahvarpour, told Iranian TV that two of the parade attackers were killed on the spot, one died from his wounds at a hospital and a fourth was arrested.
Rouhani and other top officials were shown on Iranian TV leaving another military parade in Tehran, immediately after they were told about the attack in Khuzestan.
Parades were held across the country in commemoration of the start of Iran’s 1980-88 war with Saddam Hussein's Iraq.
There were conflicting reports about who was responsible for the attack, but both the Islamic State group and a group calling itself the "Arab Struggle Movement for the Liberation of Ahvaz" claimed responsibility.
The ASMLA's spokesman, Yaqoub Hur al-Tastari, told the BBC Persian service the group "did not target civilians," although Iranian media claimed that several children and journalists were among the casualties.
Iranian Foreign Minister Mohamed Javad Zarif wrote in a tweet that "terrorists recruited, trained, armed and paid by a foreign regime" were responsible for the Ahvaz attack. He also said Tehran would hold "regional terror sponsors" and what he called "their U.S. masters" accountable for the attacks.
Reuters, citing Iranian state media, said Iran's government summoned the envoys of the Netherlands, Denmark and Britain on Saturday, accusing them of harboring Iranian opposition groups in their country.
Earlier, Iranian media reportedly accused both Israel and Saudi Arabia of responsibility for the attack but gave no direct evidence to support the claims.
Former Iranian President Abolhassan Bani Sadr told VOA that "there is no such thing as an independent terrorist group and there never has been." He argued that "all terrorism is the product of one or another regional powers meddling in the affairs of its neighbors."
Bani Sadr said that the "Iranian regime is at war with its own people and that it uses its military might, both inside and outside the country, to justify its existence."