Around 400 Iranian troops have been killed in Syria since the beginning of the country's civil war, according to Iranian media.
On Wednesday, the semi-official Tasnim News Agency said four more Iranian revolutionary guards were killed in Syria in the latest incident.
Revolutionary Guard is a military or paramilitary elite unit that plays the role of key protection force of the new regime in a country which has experienced a revolution.
Forces from Iran's Revolutionary Guards -- a branch of Iran's Armed Forces often called a "paramilitary elite unit" -- have lost 54 military personnel, including three high ranked officers, while supporting Bashar al-Assad's regime forces against the Syrian opposition.
On Oct. 23, Fars News Agency had quoted General Ramazan Sharif, spokesman of the Revolutionary Guards, as saying that "Iran increased the number of its soldiers in the region" as part of a new ground offensive in Syria.
Turkey and Iran have been pursuing different policies regarding the war in Syria. Iran strongly backs Syrian President Bashar Assad while Turkey has called on him to step down and condemned his regime's massacres of opposition forces and civilians.
With the support of Russian airstrikes, forces loyal to the Syrian regime army and allied Iranian and Hezbollah forces are preparing for a ground offensive against opposition forces in Aleppo, two senior regional officials familiar with the plans said in October.
"If Syria makes a request (for Iranian forces), we will study the request and make a decision," Alaedin Boroujerdi, the chairman of the Iranian parliament's national security and foreign policy committee, had said back in October. "What's important is that Iran is serious about the fight against terrorism," he added. "We have supplied aid and weapons and sent advisors to Syria and Iraq."
At least 250,000 people have been killed since the Syria conflict began in 2011, with 7.6 million internally displaced and over four million having fled to other countries.