Russia has carried out a third day of air strikes in Syria and says it had hit Islamic State's 'capital' as President Vladimir Putin faced mounting international criticism over his military campaign.
Moscow said it had bombed "an IS training camp" and a command post in the IS bastion of Raqa on Thursday, but on Friday it targeted rebel groups opposed to Syrian President Bashar al-Assad.
The US-led coalition urged Russia to stop attacking Syrian opposition forces, warning that it risked escalating the four-year civil war that has already killed up to 250,000 people.
"These military actions constitute a further escalation and will only fuel more extremism and radicalisation," seven countries including the United States, Turkey and Saudi Arabia said in a statement.
"We call on the Russian Federation to immediately cease its attacks on the Syrian opposition and civilians," it added.
Islamic State has seized control of large parts of eastern Syria and northern Iraq and is one of many groups fighting Assad.
Washington and its allies accuse Russia of using what Moscow insists is a campaign against "terrorists" as a pretext to bomb other more moderate groups that oppose Assad.
Some of the groups targeted have been supplied with training and weapons by the United States and its allies.
Several military sources and the Syrian Observatory for Human Rights, a monitoring group, said on Friday Russian air strikes had hit areas controlled by groups other than IS.
A security source said that "Russian planes conducted several strikes on military positions and command centres held by the Army of Conquest in Jisr al-Shughur ... and Jabal al-Zawiya in Idlib".
The Observatory said at least 12 IS jihadists were killed in the Raqa attack on Thursday.