Russian forces begin airstrikes in Syria

Russia on Wednesday carried out its first airstrike in Syria, near the city of Homs, a US defense official said, marking the formal start of Moscow's military intervention in the 4.5-year-old conflict.

Speaking on condition of anonymity, the defense official said a Russian general working out of an intelligence center in Baghdad had walked over to the US embassy and given a verbal communique of the impending strike.

US Defense Secretary Ashton Carter on Tuesday told the Pentagon to "open lines of communication" with Russia about military activity in Syria, where the US-led coalition is carrying out regular air attacks against the Islamic State group.