Russia has conducted a significant number of strikes in Syria, according to a US defense official. The US was informed about the strikes in advance under an agreement with Washington on air safety protocols, he added.
According to the source, a number of the strikes targeted the Islamic State stronghold in Raqqa.
On September 30, Russia launched an aerial campaign against extremist positions in Syria, following a request from President Bashar Assad.
Since the beginning of the air campaign, Russian Aerospace Forces have carried out around 1,800 sorties, destroying some 2,700 terrorist targets. Several hundred militants have been killed, and dozens of command centers and depots have been destroyed.