A deadly terrorist attack Saturday on a military parade in the southwestern Iranian city of Ahvaz, in a province bordering Iraq with many Sunni Arabs, has left at least 25 dead and 60 others injured, according to Iranian news agencies.
"First we thought it's part of the parade, but after about 10 seconds we realized it was a terrorist attack as bodyguards (of officials) started shooting", he told AFP.
However, Emirati academic Abdulkhaleq Abdulla, has tweeted on the Ahwaz attack by saying: "A military attack against a military target is not a terror act".
A claim of responsibility by the extremist group Islamic State (IS), which also took responsibility for the 2017 twin attacks on the Iranian parliament and the mausoleum of Islamic republic founder Ayatollah Ruhollah Khomeini, was dismissed by a military spokesman.
Giuliani has made similar comments before on Iran, and the State Department has said he does not speak for the administration.
Iran has previously blamed Saudi Arabia for supporting Arab separatists in the Islamic republic.
Hezbollah in a statement said "satanic and malignant hands are behind this terrorist action", and accused the United States and its allies of conducting it "directly or by proxy".
Mostafa Koshcheshm, a Tehran-based political commentator and journalist, told Al Jazeera that the al-Ahvaziya movement had been "nurtured, supported, and trained by Saudi Arabia".
Iran's Revolutionary Guards vowed on Sunday to wreak "deadly and unforgettable" vengeance for the attack, which killed 12 of their comrades, and Tehran accused USA -backed Gulf Arab states of backing the gunmen. Armed groups have engaged in sporadic clashes with security forces in the region.
Armed forces spokesman Brigadier General Abolfazl Shekarchi said three attackers were killed at the scene and the fourth died later of his injuries.
Rouhani also said the U.S. is provoking regional states against Iran, citing the terrorist attack in Ahvaz, which also left scores of people, including women and children, injured.
Trump ripped up a global deal on Iran's nuclear program in May and his administration is snapping back sanctions on the Islamic Republic, including measures on its oil exports from November 4.
But the USA has denied responsibility and says it condemns "any terrorist attack", while a senior official for the United Arab Emirates - one of the countries Mr Rouhani was thought to be referring to - called the accusations "baseless".
Iranian Foreign Minister Mohammad Javad Zarif vowed that his country will respond "swiftly and decisively".
"It is not acceptable that these groups are not listed as terrorist organizations by the European Union as long as they have not carried out a terrorist attack in Europe", Qasemi was quoted as saying by IRNA news agency.
President Trump is open to meeting with Iranian leaders at this week's UN General Assembly meeting, Pompeo said. Two U.S. -based members who joined the gathering have been targeted for assassination by alleged Iranian agents named last month in criminal complaints issued by the U.S. District Court for the District of Columbia.
None of them directly mention Saturday's attack in Ahvaz, Iran, nor do they say they're acting on behalf of ISIS, which has claimed responsibility for the attack but has not provided evidence to support that claim.
Both Iran and Saudi Arabia have been fighting for religious and political dominance for decades.
Al Jazeera's Zein Basravi, reporting from the capital Tehran, said the "attack for many Iranian communities was very personal".