Shortly before the end of 2015, reports indicated that Iran had started to withdraw elite troops from the country's Islamic Revolutionary Guard Corps from Syria. This was followed by speculation that the Iranian military presence in Syria was receding just as that of the Russians was expanding. The Russians have not commented publicly on these developments, and the Iranians have categorically denied any intention to pull out of Syria, or any frictions with Moscow in this regard. Iranian officials say that their relations with the Russians are “solid” and that they have no intention of scaling down their support for the regime led by Syrian President Bashar Al-Assad. But over the past few months a large number of Iranian officers in Syria have been killed, including no fewer than 18 generals from Iran's Badr Organisation, according to Syrian opposition forces. Samir Al-Quntar, a key Hizbullah operative, was also killed in an air raid that many assumed was carried out by Israel. There is speculation that Russia may have been involved in the killing of senior Iranian commanders, as a way of letting Iran know who's boss. At the start of its intervention in Syria, Moscow told Syrian and Iranian officials that it would not tolerate any opposition and that once the Russians deployed they would be calling the shots, Syrian sources close to the regime said. For weeks, Iran has been pulling out some of its officers and changing its strategy in the country, either to comply with Russian demands or to play for time. A senior Free Syrian Army (FSA) officer, speaking on condition of anonymity, said that Russia has taken over many of the military bases Iran used to have in Syria, the latest being the Al-Shoeirat Airbase in Homs. Iran has pulled out all its military units from Al-Shoeirat, which the Russians are refitting as a base for their helicopters, the FSA officer said. “Iran has fought complex political battles to protect its interests from Russian intervention,” the officer added. “But before sending its troops into Syria, Moscow decided that Iran could not be allowed to have a significant military presence in the country.” Russia, the same officer pointed out, does not mind Hizbullah continuing its mission in Syria. “Russian military commanders have allowed Hizbullah to stay, but they have prevented it from carrying out any operations without prior approval from them.” Another FSA commander said that Iran has 3,000 military experts in Syria. “Iran did not send fighters to Syria, only commanders and experts. Iran does not need to deploy its own fighters, not with the tens of thousands of Shiite Lebanese and Iraqi militiamen that are willing to do its bidding.” Although Iran has pulled out many of its military experts and given up strategic positions, it has continued to recruit Lebanese, Afghan and Iraqi Shiites to fight in Syria. Rather than scaling down its presence altogether, Iran seems to be accommodating the Russians while keeping its options open. Iran has something the Russians lack, which is a strong sectarian affiliation with the Syrian regime. At a later stage in the conflict, the Iranians and the regime may indeed turn against the Russians. There is an advantage, however, for Iran in scaling down its operations in Syria. The cost of supporting the Al-Assad regime has proven to be more costly than Tehran expected. But it is hard to believe that the Iranians will now just bow out and let Moscow run the show in Syria. Iran is too invested in Syria and the region to allow this to happen. If Tehran were to pull out of Syria, this might compromise its position in other parts of the region, especially in Lebanon and Yemen. In short, the Iranians may be pleased to see the Russians pulling their weight at last in Syria, and they may even be willing to let Moscow take the lead. But pulling out of Syria or accepting a much-diminished role in the country is out of the question. Iranian strategists may also be hoping that the Russians, who are reluctant to put their boots on the ground in Syria, will ultimately need their help. Air raids alone cannot end the current conflict, and even the Russians must be aware of that.