BEIRUT (Reuters) - While Russian fighter planes pound rebel positions on the battlefield in Syria, Russian military strategists are playing a far more subtle role in support of President Bashar al-Assad.

A man sprays water on an ambulance at a site hit by what activists said were three consecutive air strikes carried out by the Russian air force, the last which hit this vehicle, in the rebel-controlled area of Maaret al-Numan town in Idlib province, Syria January 12, 2016. REUTERS/Khalil Ashawi

Several sources - on both sides of the battle lines - have told Reuters in interviews conducted over the past two months that Russian advisers have been involved in drawing up plans to secure Damascus, Assad’s seat of power.

Those interviewed by Reuters, including non-Syrian military officials fighting alongside Assad’s forces, said Russia’s plans to buttress Damascus involve weakening rebel forces in the south of the country between the capital and Jordan. The aim is to reduce the rebels’ chances of launching a major offensive.

The Russian Defense Ministry did not respond to written questions for this article. Russia has said it has no ground troops in Syria beyond those protecting its bases. Russia does concede it has trainers and advisers on the ground, but only in an educational and advisory capacity.Russia’s influence in military planning is already evident, rebel fighters and the non-Syrian military officials say.

They say Russian experts played a major role in a Syrian army offensive at the turn of the year in the western coastal province of Latakia, home to the Alawite population of which Assad is part.

That offensive helped pave the way for the Syrian army to push toward the Turkish border, cutting the insurgents’ supply lines from Turkey.DEGREES OF INVOLVEMENTThe extent of Russian involvement on the battlefield is disputed, however.

Two military officials, neither of them Syrian but both fighting alongside the Syrian army, said Russian officers and military experts had helped in the planning and directed the offensive in Latakia.

According to their account, the Russians were in charge of artillery fire and provided artillery cover, not just air strikes. “The coast battle was theirs,” said one of the sources.

A Syrian military source, speaking on condition of anonymity to Reuters in Damascus last week, said the Russians were partners, but he denied they had a leadership role.

“The Russian role in participation, in planning and executing military operations is being reinforced all the time. It is participation, not management,” said the source.

“The Russians take part in the ground and air planning, but at the end, the Syrian officers are the ones who know the land, the fronts, the geography better.”

Insurgents interviewed by Reuters, including a local commander from the Ahrar al-Sham group, also said that Russian troops took part in the fighting.

Moscow says that its main goal in Syria is to target hardline Islamist groups which pose a global threat, including to Russia.

Islamic State commander Abu Omar al-Shishani is a Chechen. He is believed to be leading thousands of fighters most of them from Chechnya and Central Asia.

CEASEFIRESPro-government sources say the Russian role has expanded to include facilitating local ceasefires in rebel-held areas around Damascus, with the aim of creating a secure buffer around the capital.Syrian Minister of National Reconciliation Ali Haidar described the process as purely Syrian even if there had at times been Russian help.

“The truth is that since the presence of the Russians on Syrian land, they can play the role of mediator in some areas,” he said at his offices in Damascus. “The Russians make contact (with militants) when they can, of course - in Douma and other areas,” he said, in reference to an area east of Damascus.”Sometimes it is the militants who request mediation by the Russians,” he said. Those wishing to relocate wanted guarantees of safe passage to rebel strongholds, and those wishing to stay wanted to be sure they wouldn’t be killed later on, he said.According to the non-Syrian sources interviewed by Reuters, Russian advisers orchestrated two deals in which hardline Islamist fighters were evacuated from the south toward areas their groups control in the northern and central provinces.

One of the non-Syrian military sources said the Russians worked “in the shadows” to facilitate the ceasefire deals. In some cases the Russians operated as guarantors for the deals.

Dozens of cars left southern towns of Syria in December carrying fighters from Nusra Front with their families to the northern province of Idlib which is under control of an alliance of rebels including Nusra Front.Weeks later a convoy left Hajar al-Aswad and Yarmouk camp areas near Damascus carrying fighters and families from Islamic State to the group’s stronghold of Raqqa.

A second source who was informed of the deals said the fighters were given safe passage. The aim was to empty these areas of hardline Islamists so clearing the way for the government to strike deals with the remaining rebels.

“The Russians want all the battles to be focused in the north, they want the south and Damascus and the coastal line all neutralized. Ultimately they are working toward achieving a wider political solution,” said the source.

The Syrian government and its allies accuse the opposition and the insurgents of blocking efforts to end the fighting and reach a political deal.