MOSCOW: Russia has begun its first military operations in Syria by sending in 28 war planes as it becomes more deeply involved in the conflict, according to American officials.
The officials said 12 fighter jets and 12 close support aircraft had arrived in recent days at a Syrian air base in Latakia, where four jets were stationed last week.
Russian drones have also started surveillance flights, the Americans said.
Yesterday (Monday) Novaya Gazeta, an independent Russian newspaper, reported that Moscow might launch "demonstrative" strikes in support of Bashar al-Assad's embattled Syrian government in the coming days, before President Vladimir Putin is due to speak to the UN general assembly next week.
The apparent increase in the flow of Russian arms and personnel to Syria has prompted speculation that the Kremlin may be preparing for direct military intervention on Assad's side. Russian military officials have confirmed that they are expanding and modernising a naval base at Tartous and an airbase in nearby Latakia, but have denied plans to intervene directly in the war.
Novaya Gazeta quoted an unnamed senior military source saying Russia was considering a limited operation that confirms the "seriousness" of its intentions. The source said the idea was to carry out a small but highly visible operation, possibly involving air or artillery strikes against Isil.
Alexander Golts, an independent Russian military analyst, said such an operation, which would not put ground troops at risk, would be "the most rational approach" if the Kremlin was determined to use its military build-up in Syria to score diplomatic points.
But he said that a grand international coalition envisaged by Mr Putin would be almost impossible to put together because of disagreements about whether Assad is a legitimate leader of Syria.
"All Russian policy in Syria is very clearly directed at overcoming international isolation because of Ukraine," Mr Golts said. "The idea is to prevent a repetition of the G20 summit in Australia in 2014, when Mr Putin found himself completely alone."
Mr Putin defended the military build-up in a meeting about Syria with Benjamin Netanyahu, the Israeli prime minister, in Moscow.
Mr Putin said Russia's actions in the Middle East "have been and always will be very responsible". He also insisted there was no threat to Israel from the Russia-Syria alliance.
Meanwhile, the Russian foreign ministry called for international action after a mortar shell hit the Russian embassy in Damascus.