Correction: An earlier version of this article incorrectly said that Grand Ayatollah Ali Sistani last week issued a fatwa to all Shiites that many Iraqi Shiites in Iran are interpreting as a call to prepare to fight ISIS militants. Sistani’s fatwa was addressed to all Iraqis.

Thousands of Iranians have signed up online or at religious offices throughout the Islamic republic to join Iraq’s fight against advancing al-Qaeda-inspired militants, but the volunteers, many of them of Iraqi origin, are unlikely to see combat anytime soon.

While Iran’s leaders and many Shiites living here have offered whatever it might take to bolster Iraq’s government and defend Shiite holy sites, the public show of support is taking the form of cheerleading for now, not the dispatch of organized fighting forces.

Analysts and leaders of Tehran’s Iraqi community say any support from Iran will be subtler, confined to military planning and strategy rather than manpower — the same kind of support Iran provided during earlier sectarian conflicts in Iraq and, more recently, to Syria’s president, Bashar al-Assad. According to unconfirmed reports, commanders of the Iranian Revolutionary Guard Corps’s elite Quds Force are already assisting Iraqi forces in the current fight.

“The Islamic republic can help them with crisis management, the way Iran trained the Syrians during their war on how to help the system stay in power against opposition groups,” said Amir Mohebbian, a political commentator in Tehran who sees the new conflict in Iraq as an opportunity for Iran.

“Exporting the revolution does not mean military weapons and soldiers. It’s about giving good advice,” Mohebbian said.

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But people here are signing up for the fight just in case.

On Friday in Dolatabad, a dusty southern suburb of Tehran that is home to Iran’s main Iraqi enclave, community leaders held a rally to express solidarity with their compatriots battling to fend off the Islamic State of Iraq and Syria (ISIS) and to protect the Iraqi Shiite cities of Karbala and Najaf.

“We’re sending a message to the world that Iraqis living in Iran, although we are few in number, have a strong voice and we’re ready to defend our homeland and our sacred sites,” said Majid Ghamas, the Islamic Supreme Council of Iraq’s representative in Iran.

Copies of a very basic form intended to create a database of possible conscripts circulated among the crowd. Among the requirements: an Iraqi identification number and address.

“We’re here to show that we’re standing with our leaders, and if there’s a call for us to join the jihad, we’ll go,” said Seyed Jaffari, a 17-year-old high school student. “We’ll even become martyrs for Iraq. Whatever it takes to protect our country and religion.”

Several hundred people attended the rally, but most said they would join the fray only if specifically called on to do so by Grand Ayatollah Ali Sistani, whom most Arab Shiites worldwide consider their highest religious authority.

Sistani issued a fatwa last week to all Iraqis “able to bear arms” that many here in Iran interpret as a call to be prepared while also acknowledging its stipulation that Iraqis, Shiite and Sunni alike, must be allowed to defend themselves against ISIS militants without the intervention of foreign forces.

“Iran’s help is not about sending forces or weapons. It’s about spiritual support,” Mohamed Majed Abas Al-Sheikh, Iraq’s ambassador to Iran, who appeared at the rally, said later Friday.

The ambassador denied that Iranian fighters were already present in Iraq.

“The Iraqi government and its people reject these claims,” he said. “We have enough people inside Iraq to defend ourselves, and it is not the job of others to defend Iraq. Iraqis must do it.”

The two countries’ porous border, which has seen a huge increase in pilgrim and other traffic since the 2003 U.S.-led invasion of Iraq toppled Saddam Hussein, makes it hard to track accurately whether any fighters are entering Iraq from Iran.

Among the Iraqi Shiite communities scattered across the Middle East, the one in Iran — numbering fewer than 250,000 people, according to its leaders — has been fairly prosperous, another reason its members might be unlikely to actually risk their lives in battle.

“Iraqis in Syria are more likely to return to fight than Iraqis in Iran,” said Mohammad Ali Shabani, a Tehran-based researcher on Iraq policy. “I have a tough time seeing most of those who have chosen not to return after 2003 going back to Iraq at this time.”

Many of those who took part in Friday’s rally were middle-class Iraqis who moved to Iran during Hussein’s brutal rule. Since the U.S.-led invasion, some have returned to Iraq, while others never have, but they all acknowledge a common identity that their Iranian-born children do not feel.

“I don’t think it will get to the point that we’re needed, but I wish it would,” said Aziz Moshfegh, a 60-year-old furniture company owner who said he moved to Iran when he was 20. “We are here today to encourage those who are fighting. Believe me, if Ayatollah Sistani’s fatwa was general and directed to everyone, the entire Muslim world would join the fight.”