The UAE has said that it will join any US-led ground operation in Syria, as Iran sends in more troops REUTERS/Ben Job

Iran has ramped up the number of troops sent to fight in Syria in recent weeks, with tens of thousands of ground troops sent to combat opposition forces.

The exiled opposition group National Council of Resistance of Iran (NCRI) has claimed the Islamic republic has sent tens of thousands of revolutionary guards (IRGC) and non-Iranian fighters to Aleppo, where civilian casualties and injuries among fighters are reported to be high, in a bid to boost President Bashar al-Assad.

The increase in the number of Iranian boots on the ground comes as Syria's foreign minister Walid al-Moallem said on Saturday (6 February) that any foreign troops entering the country without permission "would go home in wooden coffins".

His comments followed the offer from Saudi Arabia to send in ground troops as part of the US-led offensive against Isis, although the kingdom did not say how many troops would be available.

Despite al-Moallem's warning that the intervention of foreign ground troops would be seen as an act of aggression, the UAE announced that it too would be prepared to join the fight against Isis in the war-torn country.

The Emirates said yesterday (7 February) that it would join ally Saudi Arabia in sending ground troops, if required, with numbers not yet confirmed. US senator John McCain has called for 100,000 troops, mostly from Sunni Muslim states, to be sent into Syria.

Troops from Iran are believed not to have engaged Isis fighters in combat thus far, instead fighting the Free Syrian Army and other opposition forces.

According to reports from inside the Iranian regime, following the lifting of sanctions, the supreme leader Ayatollah Khamenei has ordered extra resources to be allocated to the IRGC, Hezbollah and the militias for the war in Syria.