"If the Syrian government asks us to send forces to Syria, we will study their request," Araghchi said in an excerpt from an interview published on his official Telegram channel.

Iran and Syria have been close allies for decades and Iran has long provided military advisors to the Syrian armed forces.

On Monday, foreign ministry spokesman Esmaeil Baghaei said Iran's "military advisors were present in Syria, and they are still present" and would remain in the country "in accordance with the wishes" of its government.

The Iranian government has been portraying the rebel assault as a US-Israeli plot to destabilise the Middle East.

On Tuesday, the chief of the Iranian armed forces, General Mohammad Bagheri, called the rebel advance "dangerous for the region" according to state television.

Bagheri held separate talks on Syria with his Iraqi and Syrian counterparts, as well as the Russian Defence Minister Andrei Belousov.

They all said they would "take the necessary measures to support the Syrian army", according to Iranian state television.