18,000 Shia militiamen fight for Syria's Assad: Sources

Around 18,000 Shia militiamen are believed to be fighting alongside the Bashar al-Assad regime in Syria, which has been ravaged by a vicious civil war since 2011, local sources told Anadolu Agency.

The sources, who did not divulge themselves for security concerns, said Shia militias were intensively engaged in military operations against opposition forces in the country's southern part.

About 9,000 Shia militiamen are deployed in the southern Aleppo province in north-west Syria, while 5,000 are fighting in the provinces of Damascus, Daraa and Quneitra, which are known as the “southern front", the sources said.

According to the sources, around 2,000 Shia militiamen are also deployed in the eastern part of Homs and Latakia provinces.

Syria has remained locked in a vicious civil war since early 2011, when the Assad regime cracked down on pro-democracy protests -- which erupted as part of the "Arab Spring" uprisings -- with unexpected ferocity.

Since then, more than 250,000 people have been killed, according to UN figures.

The Syrian conflict has also drawn neighboring Iran, which has deployed forces to back the Assad regime against the heavily-armed opposition forces.

According to Iranian media reports, more than 400 Iranian soldiers have been killed in the fighting in Syria since the conflict began in 2011.

The six-year conflict also drew the Lebanese Shia group Hezbollah, which is backed by Shia Iran.

According to estimates, at least 10,000 Hezbollah fighters are believed to be fighting alongside the Assad forces across Syria.

Thousands of Hezbollah fighters are also believed to have been killed in the conflict. The Shia group did not confirm these casualties.

Iraqi Shia militias follow the Hezbollah as the most influential groups fighting alongside the Assad regime in Syria.

These militias, which are drawn from Iraq's predominantly Shia areas as Baghdad, Najaf and Basra, are estimated to number nearly 5,000.

There are also other militias as Pakistani Zaynabiyyun Brigades, which has more than 500 members and are fighting in the north of Aleppo, and the Afghan Fatimiyun Brigade, which has about 2,000 fighters in south of Aleppo, Damascus and Daraa.

The Assad regime is using local militia groups known as “shabiha" to bolster its forces against the opposition.

The shabiha, which is blamed for the killing of many anti-Assad protesters, is estimated to be composed of 24,000 members.

In the first year of the conflict, the shabiha militiamen began to replace soldiers deserting the army. Their numbers began to increase significantly as the regime forces lost power.

The shabiha is believed to be funded by pro-regime tribal leaders and businessmen, including Assad's cousin Rami Makhlouf.

*Anadolu Agency correspondent Servet Gunerigok contributed to this report from Ankara