The first group of Russian war planes has left Russia's Hmeymim air base in Syria and begun the long journey home, Russia's Defence Ministry said on Tuesday.

The group included Sukhoi-34 fighter-bombers. The ministry said each group will be led home by either a Tupolev-154 passenger plane or an Ilyushin-76 transport aircraft carrying engineers, technical personnel, and cargo.

Earlier, Russian state television showed personnel at Russia's air base in Syria loading transport aircraft for return to Russia a day after President Vladimir Putin ordered most of his country's military contingent there to start to withdraw.

The images, broadcast on the Rossiya 24 TV station, showed personnel loading equipment and boxes onto Ilyushin Il-76 heavy lift transport aircraft at Russia's Hmeymim air base in Latakia province.

The Kremlin has used the base, which Putin said Russia would keep along with a naval facility at Tartous, to mount a five-month campaign of air strikes to support Syrian President Bashar Al-Assad, an intervention that has tipped the balance of power in the Syrian leader's favour.

Putin announced on Monday that "the main part" of Russian armed forces in Syria would start to withdraw, telling his diplomats to step up the push for peace as UN-mediated talks resumed on ending the five-year-old war.

The Russian Defence Ministry said in a statement on Tuesday that technical staff had begun preparing aircraft to fly back to their bases in Russia in line with Putin's orders. Russia has maintained a strike force at the Hmeymim base of at least 50 aircraft and helicopters.

"The personnel are loading equipment, logistics items and stock onto transport aircraft," the ministry said.

"Aircraft from the Hmeymim base will fly back to the airfields where they are permanently based on Russian territory accompanied by military transport aircraft."

It said the planes would break their journey home of more than 5,000 km to refuel at intermediary bases inside Russia.

A weather forecaster on Rossiya 24 said their precise flight paths home were secret, and that it was only possible to talk of the "most convenient routes" transiting Iraq, Iran and Azerbaijan. - Reuters