Iran's Islamic Revolutionary Guards Corps (IRGC), which have been fighting in the ranks of the Bashar al-Assad regime in Syria, sent some 120 Syrian mercenaries to Yemen to fight on the side of the Houthi militias, according to local sources on Friday.

Previously, members of Iran-backed terrorist groups in the Deir ez-Zor province of eastern Syria, the mercenaries will be on an Iranian payroll of $400-500 per month, the sources said on condition of anonymity.

They will be sent to the conflict zones in the war-torn country after a week of training in the capital Sana'a, they noted, adding that depending on the performance of the first group of mercenaries, more fighters could be dispatched to Yemen in the near future.

Yemen has been ravaged by violence and instability since 2014 when Houthi rebels captured much of the country, including the capital, Sanaa.

The crisis escalated in 2015 when a Saudi Arabia-led coalition launched a devastating air campaign to roll back Houthi territorial gains.

It has since caused one of the world's worst man-made humanitarian crises with 80% of the population in need of assistance and protection./aa