TEHRAN (Dispatches) – Leader of the Islamic Revolution Ayatollah Seyyed Ali Khamenei said on Monday that the terrorists who martyred 25 people at a military parade were paid by Saudi Arabia and the United Arab Emirates, and Iran would "severely punish” those behind the attack.
"Based on reports, this cowardly act was the work of those very individuals who are rescued by the Americans whenever they are in trouble in Iraq and Syria and who are funded by the Saudis and the United Arab Emirates,” Ayatollah Khamenei said.  
The Leader, who was speaking to a group of Iranian athletes, said the attack "once again shows the Iranian nation faces many enemies on its proud path of progress and development".
"We will most certainly rigorously punish the perpetrators of this attack," he added.
Tens of thousands of Iranians on Monday attended a mass funeral service for the victims of the weekend attack amid pledges of vengeance.
The father of 4-year-old victim Muhammad Taha lay atop his son's flag-draped coffin sobbing, a public display of grief near the Sarallah Mosque in Ahvaz, the capital of Iran's oil-rich province of Khuzestan.
Women in long black chadors held back tears while rhythmically striking their chests, a traditional way of showing grief. Mourners also played drums, cymbals and horns, according to local customs.
Of the 25 martyred, 12 were from Ahvaz and the rest from elsewhere in Khuzestan.
As crowds flowed down Ahvaz's streets, cries of "Death to America" and "Death to Israel" rose from the mourners. While a traditional chant in the years since the 1979 Islamic Revolution, they have taken on a new meaning as Iran has directed anger at the U.S. and its regional allies for backing terrorists.
Speaking at the funeral, the acting commander of the Islamic Revolution Guards Corps (IRGC) Gen. Hussein Salami vowed revenge against the perpetrators and the "triangle" of Saudi Arabia, the occupying regime of Israel and the United States.
"You are responsible for these actions; you will face the repercussions," the general said. "We warn all of those behind the story, we will take revenge."
Intelligence Minister Mahmoud Alavai told the mourners that his agency had identified many suspects involved in the attack and "a majority of them were detained."  
"We will punish the terrorists, one by one," he promised the crowd.
"The terrorists themselves have perished, our agents will identify their remnants and supporters to the last man. A major part of them have already been arrested," Alavi said.  
Saturday's attack targeted one of many parades in Iran marking the start of the country's long 1980s war with Iraq, part of a commemoration known as "Sacred Defense Week." The attacks in Ahvaz sent women and children fleeing alongside the soldiers once marching in the parade.
President Hassan Rouhani has accused a U.S.-allied regional country of supporting the attackers. Iran's Foreign Ministry also summoned Western diplomats and an envoy from the UAE for providing havens for the terrorists.
Saudi-linked media immediately carried claims of responsibility by the separatists after the attack and have widely covered their previous attacks on oil pipelines.
At Monday's funeral, those attending rallied around the Iranian government and its soldiers. Cries and wails erupted at the sight of the casket of a local hero, 54-year-old Hussein Monjazi, a disabled war veteran and IRGC member who had lost a leg and a hand in the Iraq-Iran war. A photo of his crumpled body out of his wheelchair after the attack shocked the country, as did the death of the four-year-old boy.
Mahmoud Falaki, a teacher attending the funerals, said the ceremony showed Iranians "are always ready to sacrifice ourselves for our country. The terrorists are a bunch of cowards."
Another Ahvaz resident, Qaseem Farhani, said: "Just look at the crowd, with no fear, people are gathered here to see their soldiers and martyrs off to heaven."