Russia has begun air strikes against rebel positions within Syria, with the first target near the western city of Homs, US defence officials say.

Homs is not under Islamic State control, but has been central to other rebel groups fighting against Bashar al-Assad since the outbreak of the way four years ago. Russia’s choice of Homs as their first target demonstrates that the the Kremlin is moving towards a more direct role in the Syrian conflict and plans to prop up the embattled regime.

The Kremlin has declined to confirm the strikes, but the US was informed in advance. A US defence official said that a Russian official informed the US embassy in Baghdad that Russia had begun flying aerial missions over Syria and requested that the US-led coalition avoided Syrian air space during the strikes.

The strikes follow a unanimous vote by the Russian parliament to give Vladimir Putin to deploy Russian military forces within Syria.

The US criticised the Russian decision to launch strikes independent of the anti-IS coalition, and said that US operations within Syria and Iraq would be unaffected by Russia’s decision.

The US and its allies currently targets IS positions within Syria and Iraq, and has on occasion struck positions held by other Islamist groups including the al-Qaeda affiliate Jabhat al-Nusra.

#Syria: Video made by Syrian activists allegedly shows #Russia|n fighter jets flying over #Hama today. pic.twitter.com/sykNiK9j99

— Sakir Khader (@sakirkhader) September 30, 2015