The Russian military says it has begun scaling back its deployment to Syria more than two years after Moscow's intervention in the conflict on the side of the Damascus regime.

Valery Gerasimov, the chief of Russia's general staff, said there would be a "extensive" reduction of troops by the end of this year. He spoke after President Vladimir Putin said that a military campaign in Syria was coming to an end.

Here is what you need to know about the Russian army's presence in Syria.

- How many troops? -

The precise number of Russian troops fighting in Syria is not known.

Many in the country still harbour painful memories of the Soviet Union's disastrous venture into Afghanistan in 1979, with the decade-long conflict claiming the lives of more than 14,000 Soviet troops.

Putin ruled out dispatching ground troops in Syria, making the air force the mainstay of Moscow's Syria campaign. Officials have also acknowledged the presence of Russian advisors and military police in Syria.

The reality however is more complicated.

Independent Russian military expert Pavel Felgenhauer said up to 10,000 Russian troops and private contractors could have been deployed to Syria.

He suggested that Russia had between 4,000 and 5,000 Russian military servicemen in Syria including personnel at Russia's airbase in Khmeimim, a stronghold of President Bashar al-Assad in northwest Syria, and the Tartus naval facility.

On top of that, Felgenhauer said, some 2,000 to 3,000 military "advisors" helped the Syrian army gain an upper hand over rebels and jihadists on the ground.

Aside from these forces, Moscow has sent military police, mainly made up of Chechen battalions deployed to regions retaken from rebels forces like Aleppo.

Felgenhauer estimated there are also "up to a thousand" military police and special forces fighting alongside regime troops.

Officials and observers also point out the presence of Russian mercenaries in Syria, including those working for the private military company dubbed Wagner.

Felgenhauer estimated the number of mercenaries at 2,000 to 3,000.

- How many casualties? -

Around 40 Russian servicemen have reportedly been killed in Syria since Moscow's intervention. The Kremlin has acknowledged some of those deaths.

But the losses may be much higher given the number of Russian troops and mercenaries believed to be in the country.

- Fighter planes, bombers -

The role of the Russian air force has been celebrated at home. It is unclear how many aircraft have been deployed but Felgenhauer said "several dozens" of war planes and "several dozens" of helicopters were currently in the country.

Bomber planes such as the Tu-22 and Tu-160 have also flown from Russia to hit targets in Syria.

- Navy, aircraft carriers -

Russian warships and submarines have also played a prominent role backing up the bombing campaign in Syria, firing missiles at Islamic State group targets from the Mediterranean.

Moscow's Khmeimim airbase in Latakia province and naval facility in Tartus have been protected by S-300 and S-400 air missile defense systems.

Russian ships, such as Moscow's only aircraft carrier the Admiral Kuznetsov, also completed missions in Syria.

- What next? -

The significant retreat Gerasimov spoke of was not the first time Russia promised to wind down operations in Syria.

Putin first said in March 2016 that the country's military campaign in Syria was coming to an end.

Today few believe Russia is leaving the war-torn country any time soon, with analysts saying its military presence could be used as a bargaining chip during sputtering peace negotiations.

"Russia will not quit Syria, it did not fight for that. It fought so that it could stay," Felgenhauer said.

"These last two years, we heard announcements about retreat several times but, in fact, Russian presence has only increased," he said.

The military base in Khmeimim, hastily set up at a civilian airport in 2015 to welcome Russian planes, has became a permanent Russian base following an agreement between Damascus and Moscow.

Source: AFP