Participants welcome a Russian military pilot upon his return to a home airbase from Syria, during a traditional bread and salt ceremony in Buturlinovka in Voronezh region, Russia, March 15, 2016. (Photo by Olga Balashova/Reuters/Russian Ministry of Defence)





Participants greet a Russian military pilot upon his return to a home airbase from Syria, during a welcoming ceremony in Buturlinovka in Voronezh region, Russia, March 15, 2016. (Photo by Olga Balashova/Reuters/Russian Ministry of Defence)





Participants attend a ceremony to welcome Russian military jets and pilots upon their return to a home airbase from Syria, in Buturlinovka in Voronezh region, Russia, March 15, 2016. (Photo by Olga Balashova/Reuters/Russian Ministry of Defence)





A Russian pilot (L) walks near a Sukhoi Su-25 fighter jet shortly before the take-off, part of the withdrawal of Russian troops from Syria, at Hmeymim airbase, Syria, March 15, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





A Russian Sukhoi Su-25 fighter jet takes off during the withdrawal of Russian troops from Syria at Hmeymim airbase, Syria, March 16, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





A Russian pilot (L) shakes hands with a member of support personnel shortly before the take-off, part of the withdrawal of Russian troops from Syria, at Hmeymim airbase, Syria, March 15, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





A Russian pilot touches a Sukhoi Su-25 fighter jet shortly before the take-off, part of the withdrawal of Russian troops from Syria, at Hmeymim airbase, Syria, March 15, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





Russian Sukhoi Su-25 fighter jets are seen shortly before the take-off, part of the withdrawal of Russian troops from Syria, at Hmeymim airbase, Syria, March 15, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





A Russian pilot gets inside a Sukhoi Su-25 fighter jet shortly before the take-off, part of the withdrawal of Russian troops from Syria, at Hmeymim airbase, Syria, March 15, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





A Russian military jet is seen on a runway before taking off during the withdrawal of Russian troops from Syria at Hmeymim airbase, Syria, March 16, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





Support personnel prepare a Russian Sukhoi Su-25 fighter jet before the take-off, part of the withdrawal of Russian troops from Syria, at Hmeymim airbase, Syria, March 16, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





A Russian Sukhoi Su-30 fighter jet is seen on a runway shortly before taking off, part of the withdrawal of Russian troops from Syria, at Hmeymim airbase, Syria, March 16, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





Support personnel prepare a Russian Sukhoi Su-24 front-line bomber before the take-off, part of the withdrawal of Russian troops from Syria, at Hmeymim airbase, Syria, March 16, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





A Russian Sukhoi Su-24 front-line bomber is seen on a runway shortly before taking off, part of the withdrawal of Russian troops from Syria, at Hmeymim airbase, Syria, March 16, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





A Russian Sukhoi Su-24 front-line bomber is seen on a runway shortly before taking off, part of the withdrawal of Russian troops from Syria, at Hmeymim airbase, Syria, March 16, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





Russian military aircrafts ascend shortly after taking off, part of the withdrawal of Russian troops from Syria, at Hmeymim airbase, Syria, March 16, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





A Russian Sukhoi Su-25 fighter jet is seen on a runway in the rain shortly before taking off, part of the withdrawal of Russian troops from Syria, at Hmeymim airbase, Syria, March 16, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





Russian Sukhoi Su-25 fighter jets are seen on a runway shortly before taking off, part of the withdrawal of Russian troops from Syria, at Hmeymim airbase, Syria, March 16, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





Russian pilots sit inside a cabin of a military aircraft before the take-off, part of the withdrawal of Russian troops from Syria, at Hmeymim airbase, Syria, March 16, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





A Russian Sukhoi Su-24 front-line bomber is seen on a runway shortly before taking off, part of the withdrawal of Russian troops from Syria, at Hmeymim airbase, Syria, March 16, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





A Russian pilot gets inside a Sukhoi Su-25 fighter jet before the take-off, part of the withdrawal of Russian troops from Syria, at Hmeymim airbase, Syria, March 16, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





A Russian pilot gets inside a Sukhoi Su-25 fighter jet before the take-off, part of the withdrawal of Russian troops from Syria, at Hmeymim airbase, Syria, March 16, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





A Russian Ilyushin Il-76 military transport aircraft is seen on a runway shortly before taking off, part of the withdrawal of Russian troops from Syria, at Hmeymim airbase, Syria, March 16, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





Russian Sukhoi Su-25 fighter jets take off as part of the withdrawal of Russian troops from Syria at Hmeymim airbase, Syria, March 16, 2016. (Photo by Vadim Grishankin/Reuters/Russian Ministry of Defence)





Servicemen throw a pilot in the air as they gather to welcome Russian military aircraft and pilots upon their arrival from Syria during a ceremony at an airbase in the town of Primorsko-Akhtarsk in Krasnodar region, southern Russia, March 16, 2016. (Photo by Sergey Pivovarov/Reuters)





Russian Sukhoi Su-25 fighter jets are pictured after arriving from Syria, at an airbase in Krasnodar region, southern Russia, in this March 16, 2016 handout photo by the Russian Ministry of Defence. (Photo by Olga Balashova/Reuters/Russian Ministry of Defence)





Russian Sukhoi Su-25 fighter jets fly in formation after returning from Syria, before landing at an airbase in Krasnodar region, southern Russia, in this March 16, 2016 handout photo by the Russian Ministry of Defence. (Photo by Olga Balashova/Reuters/Russian Ministry of Defence)





Servicemen take part in a ceremony to welcome Russian military aircraft and pilots after they arrived from Syria, at an airbase in Krasnodar region, southern Russia, in this March 16, 2016 handout photo by the Russian Ministry of Defence. (Photo by Olga Balashova/Reuters/Russian Ministry of Defence)





A Russian Sukhoi Su-25 fighter jet arriving from Syria lands at an airbase in Krasnodar region, southern Russia, in this March 16, 2016 handout photo by the Russian Ministry of Defence. (Photo by Olga Balashova/Reuters/Russian Ministry of Defence)





A pilot receives flowers during a ceremony to welcome Russian military aircraft and pilots arriving from Syria, at an airbase in Krasnodar region, southern Russia, in this March 16, 2016 handout photo by the Russian Ministry of Defence. (Photo by Olga Balashova/Reuters/Russian Ministry of Defence)