At least 25 people are dead and 53 wounded after an army parade in the southwestern Iranian city of Ahvaz came under attack by militants on Saturday, according to state media.

Nearly half of the dead are members of the Revolutionary Guards, according to state news agencies, making this one of the worst attacks ever on the elite force.

While the Islamic State has claimed responsibility for the attack, there are conflicting reports over who is behind it. A spokesman for Iran's Revolutionary Guards, Ramezan Sharif, said the attackers were funded by Sunni arch rival Saudi Arabia.

"Those who opened fire on civilians and the armed forces have links to the Ahvazi movement," Guards spokesman Ramezan Sharif told ISNA. "They are funded by Saudi Arabia and attempted to cast a shadow over the Iranian armed forces." Zarif vowed Iran would "respond swiftly and decisively in defence of Iranian lives". -France24

Iranian Foreign Minister Mohammad Javad Zarif, however, blamed a US ally in the region - tweeting "Terrorists recruited, trained, armed & paid by a foreign regime have attacked Ahvaz. Children and journos among casualties. Iran holds regional terror sponsors and their US masters accountable for such attacks. Iran will respond swiftly and decisively in defense of Iranian lives."

Terrorists recruited, trained, armed & paid by a foreign regime have attacked Ahvaz. Children and journos among casualties. Iran holds regional terror sponsors and their US masters accountable for such attacks. Iran will respond swiftly and decisively in defense of Iranian lives. pic.twitter.com/WG1J1wgVD9 — Javad Zarif (@JZarif) September 22, 2018

Brigadier General Abolfazl Shekarchi, a senior spokesman for Iran’s armed forces, said that the attackers have ties to the US and Israel, and that weapons were hidden near the the parade route several days in advance.

The gunmen were trained by two Gulf Arab states and had ties to the United States and Israel, according to Shekarchi. “They are not from Daesh (Islamic State) or other groups fighting (Iran’s) Islamic system ... but they are linked to America and (Israel’s intelligence agency) Mossad,” he told state news agency IRNA. -Reuters

"All four terrorists were quickly neutralized by security forces," Shekarchi told state television, adding: "A four-year-old girl and a wheelchair-bound war veteran were among the dead."

تصاویری از حمله تروریستی به رژه نیروهای مسلح در اهوازhttps://t.co/Y8KIdxlpE4 pic.twitter.com/Qt0NPsXyVx — خبرگزاری ایسنا (@isna_farsi) September 22, 2018

State television blamed the attack on "takfiri elements," referring to Sunni Muslim militants. Ahvaz sits right in the center of Khuzestan province, where minority Arabs have sporadically protested in the predominantly Shi'ite country.

Amid the controversy over who was actually behind the attack, Iranian President Hassan Rouhani ordered security forces to identify the attackers, according to semi-official news agency ISNA. Rouhani heads to New York next week to address the annual UN General Assembly.

“Rouhani will use the terrorist attack to justify Iran’s presence in the Middle East...The attack will strengthen the IRGC’s position inside Iran and in the region,” Tehran-based political analyst Hamid Farahvashian said, according to Reuters.

In response to the attack, Russian President Vladimir Putin said he was "appalled by this bloody crime," adding "This event once again reminds us about the necessity of an uncompromising battle against terrorism in all of its manifestations."

"The attacks are doubtlessly meant to tarnish the prestige of the IRGC, but I believe the terrorist incidents will strengthen the IRGC’s standing and even mobilize some public support," said Ali Alfoneh, senior fellow at the Washington-based Gulf Arab States Institute.

Last year, 18 people were killed in an attack at the parliament claimed by the Islamic State.