Iran is recruiting Afghan Shia fighters in their tens of thousands to step up the Islamic Republic's efforts in the Syrian war, offering them salaries to join the fight to save the government of President Bashar al-Assad.

As the conflict enters its fifth year, Iranian media has said that there are some 20,000 fighters in the Fatemiyon division, which is made up of both naturalised Afghans who lived in Iran and those who have travelled from Afghanistan.

"Five days ago, four Afghan Shia fighters were captured in southern rural Aleppo. In addition to Iranian fighters, there are also militia fighters from Lebanon, Iraq, Pakistan, and recently China," Anas al-Abdah, the secretary of the opposition Syrian Coalition's political committee, told Al Jazeera.

"Iran is recruiting fighters from Shia communities across the world to fight in Syria," continued al-Abdah, who is based in Turkey.

"Iran considers itself the one and only reference point for all Shia people in the whole world. It organises them into political, social, and military organisations, both in their local communities and abroad.

"This is part of the main mission of the Iranian regime in terms of exporting the revolution. Iran recruits, motivates, organises, finances, and trains Shias from all over the world to help support Bashar al-Assad's regime from collapsing."

Confirming the exact number of Afghan Shia fighters in Syria was impossible, but Al Jazeera spoke with a military official who said 20,000 was in the correct range.

Colonel Hussain Kenani Moghdam of Iran's Sepah Pasdaran, or Revolutionary Guards – a branch of Iran's armed forces – told Al Jazeera: "Fatemiyon … numbers in the tens of thousands; most of its fighters are already trained in Afghanistan and those that have no training get trained in Afghanistan, and enter into Syria through Iraq or Lebanon."

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He added that the Fatemiyon force could be likened to Shia-led militias in Iraq.

Meanwhile, Faris Baiush, a colonel in the Syrian opposition Free Syrian Army, told Al Jazeera that the FSA estimates that there are at least 2,000 Shia Afghan fighters currently in active battles in Syria, with most engaged in the city of Aleppo.

A report by Iran's Mashregh News, which is affiliated with the Revolutionary Guards, said that the Fatemiyon force comprises some 20,000 fighters. More than 200 of them, it added, have been killed in battles across Syria since 2013.

Rewards

Many captured Afghan Shia fighters say they are attracted to Syria by the promise of a financial reward. Salaries made by their Iranian recruits are reported to range from $500 and $1,000 a month.

Others say that joining the war is a way of escaping prison sentences on charges including drug trafficking, which often end in the death penalty in Iran.

Ghanbar Naderi, an Iranian political analyst and journalist for Kayhan International, told Al Jazeera: "There are some Afghans who are naturalised Iranians and are part of the armed forces as a foreign legion.

"They are sent to Syria to defend the holy sites and key government buildings just like Iranian nationals. A large number of these people have been killed in Syria and Iraq.

"Military links between Afghan nationals and the Iranian army have been ongoing for quite some time. Now the truth has surfaced that these people are fighting side by side [with] the Iranian, Syrian and Iraqi forces.

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"The fact that there are no jobs any more due to the economy's downturn and punitive sanctions in this country, some Afghans find it lucrative to be sent to Syria to fight and make good amount of money - between $500 to $1000, but they are not forced to go."

The Fatemiyon is just one example of Iran's growing influence in recruiting fighters in the region.

200-strong regional army

Earlier this month, Major General Mohammad Ali Jafari, commander of the Islamic Revolution Guards Corps (IRGC) – another Iranian military branch – announced that Iran commands a regional force of 200,000 young armed men in Yemen, Iraq, Syria, Afghanistan and Pakistan.

"The current developments in the region, the formation of the Islamic State of Iraq and the Levant (ISIL) and Takfiri groups, and the events that occurred in the past years are paving the ground for the emergence of Imam Mahdi, and you can now see the positive results in the readiness of nearly 200,000 young armed in Syria, Iraq, Afghanistan, Pakistan and Yemen," Jafari said, addressing a memorial ceremony in Tehran for an Iranian killed in Syria.

Video footage emerges, almost on a daily basis, of Afghan fighters killed in Syria and paraded in their coffins across Iranian cities before burial.

Many captured by the Syrian opposition say they are from Afghanistan and belong to the Fatemiyon division, which has gained a reputation for its make up and heavy losses.

It is a division of Iran's Revolutionary Guards' Quds Force – an elite special forces unit responsible for extraterritorial operations.

The brigade works under the command of Qasem Soleimani, head of Quds Force, who has risen to prominence recently to become Iran's most famous general.

Photos of Suleimani standing next to Afghan Shia fighters are available on a Facebook page dedicated to the Fatemiyon.

In a documentary broadcast by Iranian media, one commander of the Fatimiyon force, Moallem, said: "The greatest freedom-loving men from all over the world and the Islamic world have come together here in whichever way they could, and as always the Shia of Afghanistan have also felt responsible and rushed to Syria to defend our religion and the Shrine of Zainab."

Afghans reticent

There has not been a census for several decades in Afghanistan, but it is estimated that between 10 and 15 percent of the Muslim-majority population are Shia – mostly from the Hazara ethnic minority.

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In a video recorded by the Syrian opposition, one captured Afghan said: "We came from Afghanistan to Iran, and from Iran to Syria. In Iran they paid us two million toman (about $660) and told us to go to Syria to fight and protect the shrine of Zainab."

In another video, a captured Afghan Shia fighter who identifies himself as Burat-Ali, said: "I was imprisoned on drug charges with a sentence of six years … they told us the shrine of Zainab will be destroyed [by ISIL] … I came from Iran to join the war with the promise of a monthly salary of $600."

But while Iranian papers openly discuss and glorify the role of the Afghan Shia militia in the Syrian war, the Afghan media is largely silent on the subject.

Contacted by Al Jazeera, Afghan authorities did not confirm attempts by Iran to recruit Afghan Shia volunteers to join the wars in Syria or Iraq.

"There are some media reports of Afghan nationals recruited by the Iranian government to join the war in Syria," Ahmad Shakib Mustaghni, spokesman for Afghanistan's foreign ministry, told Al Jazeera.

"However, we have no credible report or proof in hand to suggest that these reports are correct, but there may be individuals who have joined the war of their own accord."

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The creation of an Afghan Shia division in the Iranian Revolutionary Guards structure is not new, and dates back to the Iran-Iraq war during the 1980s when an Afghan Shia force, the Abouzar Brigade, was formed to help fight Iraq.

Al Jazeera contacted Mohammad Mohaqiq, a serving member of the Afghan parliament and founder and chairman of the Hezb-i-Wahdat, or the People's Islamic Unity Party – the main Shia party in Afghanistan with close ties with Iran - but he refused to comment on the subject via phone.