The first group of Russian aircraft has left the Hmeimim air base in Syria for their home base in Russia, the Russian defense ministry said on Tuesday.
The move came after Moscow announced it would withdraw from Tuesday the bulk of its forces from the war-torn Middle East country, reports the Xinhua news agency.
The Guardian further quoted that the Russian defense ministry statement, as saying that the withdrawal of aircraft was being done on the orders of President Vladimir Putin.
The withdrawal of most Russian forces from Syria is being timed to coincide with the resumption of peace talks in Geneva.
The start of negotiations in Switzerland on Monday offered Putin an opportune moment to declare an official end to the five-and-a-half-month Russian air campaign that has allowed the Syrian regime's army to regain key ground and strengthen its positions ahead of the talks.
With Russia's main goals in Syria achieved, the pullback will allow Putin to pose as a peacemaker and help ease tensions with Nato member Turkey and the Gulf monarchies vexed by Moscow's military action.
At the same time, Putin made it clear that Russia would maintain its air base and a naval facility in Syria and keep some troops there. Syria's state news agency also quoted Assad as saying that the Russian military would draw down its air force contingent but will not leave the country altogether.
The Syrian presidency said Assad and Putin spoke on the phone on Monday and jointly agreed that Russia would scale back its forces in Syria. It rejected speculation that the decision reflected a rift between the allies and said the decision reflected the "successes" the two armies have achieved in fighting terrorism in Syria and restoring peace to key areas of the country.
The Syrian army said that it would continue its operations against the Islamic State group, al-Qaida's Syria branch known as the Nusra Front and other militant factions in Syria that have been designated as terrorist groups by the United Nations "with the same tempo".
In an earlier statement on Tuesday, Russia's defence ministry said its military personnel were loading equipment and materiel on cargo planes and getting ready for the withdrawal.
The ministry said that the jets would be accompanied by military transport aircraft and would be making stops at airfields in Russia for refuelling and technical checks since some are stationed more than 3,000 miles away from the Syria base.
Announcing his decision in a televised meeting with Russia's foreign and defence ministries, Putin said on Monday that the Russian air campaign had allowed Assad's military to "radically" turn the tide of war and helped create conditions for peace talks.
Putin did not specify how many planes and troops would be withdrawn. The number of Russian soldiers in Syria has not been revealed. US estimates of the number of Russian military personnel in Syria vary from 3,000 to 6,000.
Russia has also deployed more than 50 jets and helicopters to its Hemeimeem air base, in Syria's coastal province of Latakia.
