The Los Angeles Times on Saturday said a secret US intelligence assessment provided to the White House predicts that the Kremlin will order military strikes in Syria to help prop up President Bashar Assad's embattled government and to stop westward advances by Daesh and other rebel groups.

The airstrikes would be conducted by more than two dozen Russian warplanes that were surreptitiously flown to Syria over the last week, the paper claimed.

US officials said the Russian pilots turned off their planes' transponders to avoid detection, and hid by flying in close formation with Russian AN-124 Condor cargo flights, which used commercial air corridors over Iraq and Iran, the report said.

Russian-made surveillance drones began flying over embattled parts of northwest Syria this week to help identify potential targets, the report quoted US officials as saying.

The drones fly daily missions above Latakia and Hamah provinces, which are nominally held by Assad's forces, and Idlib province, which is largely controlled by rebel factions, the report said.

Daesh is not active in any of the areas, however, raising questions about Russian President Vladimir Putin's intentions in the multi-sided Syrian civil war, the report added.

The Los Angeles Times said that US President Barack Obama will sit down with Putin on Monday on the sidelines of the United Nations General Assembly. The two leaders have not held formal talks in two years, but the White House is increasingly concerned about Russia's growing involvement in Syria.

The intelligence assessment was given to Obama as part of his briefings for the meeting, which was announced Thursday, the paper added.

Source: MENA