Molkino in southwestern Russia is where the Russian 10th Special Forces Brigade is based, according to information on the Kremlin website.
The destination of the Russians arriving from Syria provides rare evidence of a covert Russian mission in Syria beyond the air strikes, training of Syrian forces and small numbers of special forces troops acknowledged by Moscow.
Kremlin spokesman Dmitry Peskov said on February 14 Russians may be in Syria but “they are not part of the armed forces of the Russian Federation.” He referred Reuters to the Defense Ministry when asked why civilians fighting in Syria return to a military base. The ministry did not immediately respond.
A duty officer at the 10th Special Forces Brigade, asked why non-military people were entering the military base, said: “Nobody enters it, as far as I am aware ... You’ve seen them, okay. But you should not believe everything ... You can maybe. But how can we comment on what other organizations do?”
More than 2,000 Russian contractors are fighting to help Syrian forces recapture land from their opponents, several sources, including one contractor, have said.
The contractors are transferred by Syrian airline Cham Wings, the sources said.
Reuters reporters saw a Syrian Cham Wings charter flight from Damascus land at the civilian airport in Rostov-on-Don on April 17 and watched groups of men leave the terminal through an exit separate from the one used by ordinary passengers.
They boarded three buses, which took them to an area mainly used by airport staff. A luggage carrier brought numerous oversized bags and the men, dressed in civilian clothes, got off the buses, loaded the bags and got back on.
The three buses then left the airport in convoy and headed south; two made stops near cafes along the way and one on the roadside. All three reached the village of Molkino, 350 km (220 miles) south, shortly before midnight.
In the village, each bus paused for a minute or two at a checkpoint manned by at least two servicemen, before driving on. About 15-20 minutes later the buses drove back through the checkpoint empty. Publicly available satellite maps show the road leads to the military facility.
The buses took men along the same route from the airport to Molkino on March 25 and April 6, a Reuters reporter saw.
Several relatives, friends and recruiters of fighters told Reuters Russian private contractors have had a training camp in Molkino since the time they fought in eastern Ukraine alongside pro-Russian separatists.
The military facility is known for its recently renovated firing range, where the military trains for counter terrorist operations, tank battles and sniper shooting, the Russian Defense Ministry website says.
Reuters contacted the owners of some of the buses transporting the groups of men from the airport. They said they rent out their buses but declined to say who to: one said a trip to Molkino could have been an excursion.
One of the buses, a white 33-year-old Neoplan with a slogan of a tourist company on its boards, was imported into Russia in 2007 and initially registered in the town of Pechory. Dmitry Utkin, identified by three sources as leader of the contractors, previously commanded a special forces unit based in Pechory.
Flurry of flights between Damascus, Tehran and Moscow
In the days following the American, British and French strike in Syria, flight websites' radars identified three of the Russian air force's IL-76 cargo planes making flights on the Damascus-Moscow and Damascus-Tehran lines.
One of the Syrian cargo planes, a YK-ATA, made at least two flights from Damascus to Moscow.
On Monday at 5:40pm, a Russian air force IL-62 passenger plane that took off from a military airfield in Moscow dropped off troops in Lattakia, a port city in northern Syria.
American intelligence agencies have also been monitoring flights on the Damascus-Tehran line, concerned Iran was arming Syrian President Bashar Assad with advanced weapons that could threaten Israel.
A YK-ATD plane has been making regular flights between the two countries in the wake of the Western strike. A look at its flight routes shows the plane took off last week from Damascus to Tehran, a two hour flight. Six hours later, the plane was back in the air returning to Syria, but this time to an airport in Aleppo, north of Homs. After several hours on the ground, the plane took off again to a Syrian air force base in Damascus. This unusual flight route was repeated at least three times over the past week, and it is believed the plane was transporting military equipment from the Revolutionary Guards to Assad's forces.
Another Syrian cargo plane, a YK-ATB, has also been making regular flights over the past week between Aleppo and Damascus.
Itamar Eichner contributed to this report.